diff --git a/Cargo.lock b/Cargo.lock
index 8ec1f81d..89bf7d6c 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -58,6 +58,11 @@ name = "bitflags"
 version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "byteorder"
+version = "1.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "cc"
 version = "1.0.10"
@@ -294,6 +299,14 @@ dependencies = [
  "stable_deref_trait 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "parity-wasm"
+version = "0.28.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "byteorder 1.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "parking_lot"
 version = "0.5.4"
@@ -640,6 +653,7 @@ dependencies = [
  "failure 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "indicatif 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "parity-wasm 0.28.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "quicli 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.39 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_derive 1.0.39 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -692,6 +706,7 @@ dependencies = [
 "checksum backtrace 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)" = "ebbe525f66f42d207968308ee86bc2dd60aa5fab535b22e616323a173d097d8e"
 "checksum backtrace-sys 0.1.16 (registry+https://github.com/rust-lang/crates.io-index)" = "44585761d6161b0f57afc49482ab6bd067e4edef48c12a152c237eb0203f7661"
 "checksum bitflags 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)" = "b3c30d3802dfb7281680d6285f2ccdaa8c2d8fee41f93805dba5c4cf50dc23cf"
+"checksum byteorder 1.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "73b5bdfe7ee3ad0b99c9801d58807a9dbc9e09196365b0203853b99889ab3c87"
 "checksum cc 1.0.10 (registry+https://github.com/rust-lang/crates.io-index)" = "8b9d2900f78631a5876dc5d6c9033ede027253efcd33dd36b1309fc6cab97ee0"
 "checksum cfg-if 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "d4c819a1287eb618df47cc647173c5c4c66ba19d888a6e50d605672aed3140de"
 "checksum clap 2.31.2 (registry+https://github.com/rust-lang/crates.io-index)" = "f0f16b89cbb9ee36d87483dc939fe9f1e13c05898d56d7b230a0d4dff033a536"
@@ -722,6 +737,7 @@ dependencies = [
 "checksum num-traits 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "dee092fcdf725aee04dd7da1d21debff559237d49ef1cb3e69bcb8ece44c7364"
 "checksum num_cpus 1.8.0 (registry+https://github.com/rust-lang/crates.io-index)" = "c51a3322e4bca9d212ad9a158a02abc6934d005490c054a2778df73a70aa0a30"
 "checksum owning_ref 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)" = "cdf84f41639e037b484f93433aa3897863b561ed65c6e59c7073d7c561710f37"
+"checksum parity-wasm 0.28.0 (registry+https://github.com/rust-lang/crates.io-index)" = "79df7454d764da3aaf4e8f696e5c4b97eb82b47abfc89850bfdcf7badfad357e"
 "checksum parking_lot 0.5.4 (registry+https://github.com/rust-lang/crates.io-index)" = "9fd9d732f2de194336fb02fe11f9eed13d9e76f13f4315b4d88a14ca411750cd"
 "checksum parking_lot_core 0.2.13 (registry+https://github.com/rust-lang/crates.io-index)" = "538ef00b7317875071d5e00f603f24d16f0b474c1a5fc0ccb8b454ca72eafa79"
 "checksum proc-macro2 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)" = "49b6a521dc81b643e9a51e0d1cf05df46d5a2f3c0280ea72bcb68276ba64a118"
diff --git a/Cargo.toml b/Cargo.toml
index bceac2c2..62b38062 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -11,6 +11,7 @@ readme = "README.md"
 console = "0.6.1"
 failure = "0.1.1"
 indicatif = "0.9.0"
+parity-wasm = "0.28"
 quicli = "0.2"
 serde = "1.0"
 serde_derive = "1.0"
diff --git a/src/lib.rs b/src/lib.rs
index e9b6f6fe..ad94d78c 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -4,6 +4,7 @@ extern crate failure;
 extern crate indicatif;
 #[macro_use]
 extern crate lazy_static;
+extern crate parity_wasm;
 extern crate quicli;
 #[macro_use]
 extern crate serde_derive;
diff --git a/src/manifest.rs b/src/manifest.rs
index 9ea770fa..60d68fa2 100644
--- a/src/manifest.rs
+++ b/src/manifest.rs
@@ -1,9 +1,13 @@
+use std::collections::BTreeMap;
 use std::fs::File;
 use std::io::prelude::*;
+use std::path::Path;
 
 use console::style;
 use emoji;
-use failure::Error;
+use failure::{Error, ResultExt};
+use parity_wasm;
+use parity_wasm::elements::*;
 use serde_json;
 use toml;
 use PBAR;
@@ -33,6 +37,7 @@ struct NpmPackage {
     repository: Option<Repository>,
     files: Vec<String>,
     main: String,
+    dependencies: Option<BTreeMap<String, String>>,
 }
 
 #[derive(Serialize)]
@@ -42,24 +47,100 @@ struct Repository {
     url: String,
 }
 
-fn read_cargo_toml(path: &str) -> Result<CargoManifest, Error> {
-    let manifest_path = format!("{}/Cargo.toml", path);
-    let mut cargo_file = File::open(manifest_path)?;
+fn read_cargo_toml(path: &Path) -> Result<CargoManifest, Error> {
+    let mut cargo_file = File::open(path.join("Cargo.toml"))?;
     let mut cargo_contents = String::new();
     cargo_file.read_to_string(&mut cargo_contents)?;
 
     Ok(toml::from_str(&cargo_contents)?)
 }
 
+/// Locates the `__wasm_pack_unstable` module section inside the wasm file
+/// specified, parsing it and returning dependencies found.
+///
+/// Crates compiled with `wasm-bindgen` can declare dependencies on NPM packages
+/// in their code and this is communicated to us, `wasm-pack`, via a custom
+/// section in the final binary.
+fn read_npm_dependencies(wasm: &Path) -> Result<BTreeMap<String, String>, Error> {
+    #[derive(Deserialize)]
+    #[serde(untagged)]
+    enum Schema<'a> {
+        V1 {
+            version: &'a str,
+            modules: Vec<(String, String)>,
+        },
+        Unknown {
+            version: &'a str,
+        },
+    }
+
+    let mut module = parity_wasm::deserialize_file(wasm)
+        .with_context(|_| format!("failed to parse `{}` as wasm", wasm.display()))?;
+    let wasm_pack_module;
+    let deps = {
+        let result = module
+            .sections()
+            .iter()
+            .enumerate()
+            .filter_map(|(i, s)| match *s {
+                Section::Custom(ref cs) => Some((i, cs)),
+                _ => None,
+            })
+            .find(|&(_i, section)| section.name() == "__wasm_pack_unstable");
+        let data = match result {
+            Some((i, section)) => {
+                wasm_pack_module = i;
+                section.payload()
+            }
+            None => return Ok(BTreeMap::new()),
+        };
+        let schema = serde_json::from_slice(data).with_context(|_| {
+            "the wasm file emitted by `wasm-bindgen` contains a \
+             `__wasm_pack_unstable` section which should describe \
+             js dependencies, but it's in a format that this \
+             `wasm-pack` tool does not understand; does `wasm-pack` \
+             need to be updated?"
+        })?;
+        let modules = match schema {
+            Schema::V1 {
+                version,
+                ref modules,
+            } if version == "0.0.1" =>
+            {
+                modules.clone()
+            }
+            Schema::Unknown { version } | Schema::V1 { version, .. } => bail!(
+                "the wasm file emitted by `wasm-bindgen` contains a \
+                 `__wasm_pack_unstable` section which should describe \
+                 js dependencies, but it's schema version is `{}` \
+                 while this `wasm-pack` tool only understands the \
+                 schema version 0.0.1; does `wasm-pack` need to be updated?",
+                version
+            ),
+        };
+
+        modules.into_iter().collect()
+    };
+
+    // Delete the `__wasm_pack_unstable` custom section and rewrite the wasm
+    // file that we're emitting.
+    module.sections_mut().remove(wasm_pack_module);
+    parity_wasm::serialize_to_file(wasm, module)
+        .with_context(|_| format!("failed to write wasm to `{}`", wasm.display()))?;
+
+    Ok(deps)
+}
+
 impl CargoManifest {
-    fn into_npm(mut self, scope: Option<String>) -> NpmPackage {
+    fn into_npm(mut self, pkg: &Path, scope: Option<String>) -> Result<NpmPackage, Error> {
         let filename = self.package.name.replace("-", "_");
         let wasm_file = format!("{}_bg.wasm", filename);
         let js_file = format!("{}.js", filename);
+        let dependencies = read_npm_dependencies(&pkg.join(&wasm_file))?;
         if let Some(s) = scope {
             self.package.name = format!("@{}/{}", s, self.package.name);
         }
-        NpmPackage {
+        Ok(NpmPackage {
             name: self.package.name,
             collaborators: self.package.authors,
             description: self.package.description,
@@ -71,12 +152,18 @@ impl CargoManifest {
             }),
             files: vec![wasm_file],
             main: js_file,
-        }
+            dependencies: if dependencies.len() == 0 {
+                None
+            } else {
+                Some(dependencies)
+            },
+        })
     }
 }
 
 /// Generate a package.json file inside in `./pkg`.
 pub fn write_package_json(path: &str, scope: Option<String>) -> Result<(), Error> {
+    let path = Path::new(path);
     let step = format!(
         "{} {}Writing a package.json...",
         style("[4/7]").bold().dim(),
@@ -91,10 +178,10 @@ pub fn write_package_json(path: &str, scope: Option<String>) -> Result<(), Error
     };
 
     let pb = PBAR.message(&step);
-    let pkg_file_path = format!("{}/pkg/package.json", path);
+    let pkg_file_path = path.join("pkg/package.json");
     let mut pkg_file = File::create(pkg_file_path)?;
     let crate_data = read_cargo_toml(path)?;
-    let npm_data = crate_data.into_npm(scope);
+    let npm_data = crate_data.into_npm(&path.join("pkg"), scope)?;
 
     if npm_data.description.is_none() {
         PBAR.warn(&warn_fmt("description"));
@@ -113,5 +200,5 @@ pub fn write_package_json(path: &str, scope: Option<String>) -> Result<(), Error
 }
 
 pub fn get_crate_name(path: &str) -> Result<String, Error> {
-    Ok(read_cargo_toml(path)?.package.name)
+    Ok(read_cargo_toml(Path::new(path))?.package.name)
 }
diff --git a/tests/fixtures/dependencies/Cargo.lock b/tests/fixtures/dependencies/Cargo.lock
new file mode 100644
index 00000000..6f3f9b88
--- /dev/null
+++ b/tests/fixtures/dependencies/Cargo.lock
@@ -0,0 +1,176 @@
+[[package]]
+name = "dtoa"
+version = "0.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "itoa"
+version = "0.3.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "num-traits"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "proc-macro2"
+version = "0.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "unicode-xid 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "proc-macro2"
+version = "0.3.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "unicode-xid 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "quote"
+version = "0.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "proc-macro2 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "quote"
+version = "0.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "proc-macro2 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "scopes-hello-world"
+version = "0.1.0"
+dependencies = [
+ "wasm-bindgen 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "serde"
+version = "1.0.32"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "serde_derive"
+version = "1.0.32"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "proc-macro2 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_derive_internals 0.20.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.12.14 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "serde_derive_internals"
+version = "0.20.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "proc-macro2 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.12.14 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "serde_json"
+version = "1.0.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "dtoa 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "itoa 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num-traits 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.32 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "syn"
+version = "0.12.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "proc-macro2 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "unicode-xid 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "syn"
+version = "0.13.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "proc-macro2 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "unicode-xid 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "unicode-xid"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "wasm-bindgen"
+version = "0.2.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "wasm-bindgen-macro 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "wasm-bindgen-backend"
+version = "0.2.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "proc-macro2 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_json 1.0.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.13.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "wasm-bindgen-shared 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "wasm-bindgen-macro"
+version = "0.2.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "proc-macro2 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_json 1.0.11 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.13.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "wasm-bindgen-backend 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "wasm-bindgen-shared 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "wasm-bindgen-shared"
+version = "0.2.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "serde 1.0.32 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_derive 1.0.32 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[metadata]
+"checksum dtoa 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)" = "09c3753c3db574d215cba4ea76018483895d7bff25a31b49ba45db21c48e50ab"
+"checksum itoa 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)" = "8324a32baf01e2ae060e9de58ed0bc2320c9a2833491ee36cd3b4c414de4db8c"
+"checksum num-traits 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "0b3c2bd9b9d21e48e956b763c9f37134dc62d9e95da6edb3f672cacb6caf3cd3"
+"checksum proc-macro2 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "cd07deb3c6d1d9ff827999c7f9b04cdfd66b1b17ae508e14fe47b620f2282ae0"
+"checksum proc-macro2 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)" = "49b6a521dc81b643e9a51e0d1cf05df46d5a2f3c0280ea72bcb68276ba64a118"
+"checksum quote 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)" = "1eca14c727ad12702eb4b6bfb5a232287dcf8385cb8ca83a3eeaf6519c44c408"
+"checksum quote 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)" = "7b0ff51282f28dc1b53fd154298feaa2e77c5ea0dba68e1fd8b03b72fbe13d2a"
+"checksum serde 1.0.32 (registry+https://github.com/rust-lang/crates.io-index)" = "c73f63e08b33f6e59dfb3365b009897ebc3a3edc4af6e4f3ce8e483cf3d80ce7"
+"checksum serde_derive 1.0.32 (registry+https://github.com/rust-lang/crates.io-index)" = "9cd9e89b8be5b611971734eaf887f1da0ce1a5b51491f04b09fe855649a84f3b"
+"checksum serde_derive_internals 0.20.1 (registry+https://github.com/rust-lang/crates.io-index)" = "a79b781fe5c4a7037a10a485249a499ea02927046360afe7e04885aad2f9c10c"
+"checksum serde_json 1.0.11 (registry+https://github.com/rust-lang/crates.io-index)" = "fab6c4d75bedcf880711c85e39ebf8ccc70d0eba259899047ec5d7436643ee17"
+"checksum syn 0.12.14 (registry+https://github.com/rust-lang/crates.io-index)" = "8c5bc2d6ff27891209efa5f63e9de78648d7801f085e4653701a692ce938d6fd"
+"checksum syn 0.13.1 (registry+https://github.com/rust-lang/crates.io-index)" = "91b52877572087400e83d24b9178488541e3d535259e04ff17a63df1e5ceff59"
+"checksum unicode-xid 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "fc72304796d0818e357ead4e000d19c9c174ab23dc11093ac919054d20a6a7fc"
+"checksum wasm-bindgen 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)" = "3d40bb360252b92b57cf5ee800c92d30ae842e41d3d84bcc4fc1d3deb72d5b02"
+"checksum wasm-bindgen-backend 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)" = "7f1a0ad26bc8fac6cbf68097e3dd4ffa40a288dda34e83bfaa7ff4626b69085d"
+"checksum wasm-bindgen-macro 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)" = "3a600fa1ce92e2e8db8f89a15baf679e5bac39561e55e750cda9fb6a317e64c3"
+"checksum wasm-bindgen-shared 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)" = "aba2057a4e843cb2d754a923d46bb62aeab1531c58a78160f392e7ded8de3637"
diff --git a/tests/fixtures/dependencies/Cargo.toml b/tests/fixtures/dependencies/Cargo.toml
new file mode 100644
index 00000000..bad6f67f
--- /dev/null
+++ b/tests/fixtures/dependencies/Cargo.toml
@@ -0,0 +1,13 @@
+[package]
+name = "dependencies"
+description = "an example rust->wasm crate"
+version = "0.1.0"
+authors = ["Michael Gattozzi <mgattozzi@gmail.com>"]
+license = "WTFPL"
+repository = "https://github.com/ashleygwilliams/wasm-pack"
+
+[lib]
+crate-type = ["cdylib"]
+
+[dependencies]
+wasm-bindgen = "0.2.4"
diff --git a/tests/fixtures/dependencies/README.md b/tests/fixtures/dependencies/README.md
new file mode 100644
index 00000000..97b39af9
--- /dev/null
+++ b/tests/fixtures/dependencies/README.md
@@ -0,0 +1,2 @@
+# scopes-hello-world
+> an example rust -> wasm project
diff --git a/tests/fixtures/dependencies/scopes-hello-world_bg.wasm b/tests/fixtures/dependencies/scopes-hello-world_bg.wasm
new file mode 100644
index 00000000..fbc5109d
Binary files /dev/null and b/tests/fixtures/dependencies/scopes-hello-world_bg.wasm differ
diff --git a/tests/fixtures/dependencies/scopes_hello_world_bg.wasm b/tests/fixtures/dependencies/scopes_hello_world_bg.wasm
new file mode 100644
index 00000000..fbc5109d
Binary files /dev/null and b/tests/fixtures/dependencies/scopes_hello_world_bg.wasm differ
diff --git a/tests/fixtures/dependencies/src/lib.rs b/tests/fixtures/dependencies/src/lib.rs
new file mode 100644
index 00000000..9e44b28c
--- /dev/null
+++ b/tests/fixtures/dependencies/src/lib.rs
@@ -0,0 +1,15 @@
+#![feature(proc_macro, wasm_import_module, wasm_custom_section)]
+
+extern crate wasm_bindgen;
+
+use wasm_bindgen::prelude::*;
+
+#[wasm_bindgen]
+extern {
+    fn alert(s: &str);
+}
+
+#[wasm_bindgen]
+pub fn greet(name: &str) {
+    alert(&format!("Hello, {}!", name));
+}
diff --git a/tests/manifest/add.wasm b/tests/manifest/add.wasm
new file mode 100644
index 00000000..fbc5109d
Binary files /dev/null and b/tests/manifest/add.wasm differ
diff --git a/tests/manifest/dependencies.wasm b/tests/manifest/dependencies.wasm
new file mode 100644
index 00000000..267a4353
Binary files /dev/null and b/tests/manifest/dependencies.wasm differ
diff --git a/tests/manifest/main.rs b/tests/manifest/main.rs
index 813087d6..06072fa4 100644
--- a/tests/manifest/main.rs
+++ b/tests/manifest/main.rs
@@ -8,19 +8,20 @@ mod utils;
 
 use std::fs;
 
+use utils::FailureExt;
 use wasm_pack::manifest;
 
 #[test]
 fn it_gets_the_crate_name_default_path() {
     assert!(manifest::get_crate_name(".").is_ok());
-    assert_eq!(manifest::get_crate_name(".").unwrap(), "wasm-pack");
+    assert_eq!(manifest::get_crate_name(".").unwrap_pretty(), "wasm-pack");
 }
 
 #[test]
 fn it_gets_the_crate_name_provided_path() {
     assert!(manifest::get_crate_name("tests/fixtures/js-hello-world").is_ok());
     assert_eq!(
-        manifest::get_crate_name("tests/fixtures/js-hello-world").unwrap(),
+        manifest::get_crate_name("tests/fixtures/js-hello-world").unwrap_pretty(),
         "js-hello-world"
     );
 }
@@ -28,12 +29,13 @@ fn it_gets_the_crate_name_provided_path() {
 #[test]
 fn it_creates_a_package_json_default_path() {
     let path = ".".to_string();
-    wasm_pack::command::create_pkg_dir(&path).unwrap();
+    wasm_pack::command::create_pkg_dir(&path).unwrap_pretty();
+    utils::mock_wasm(path.as_ref(), "wasm_pack");
     assert!(manifest::write_package_json(&path, None).is_ok());
     let package_json_path = format!("{}/pkg/package.json", &path);
     assert!(fs::metadata(package_json_path).is_ok());
     assert!(utils::read_package_json(&path).is_ok());
-    let pkg = utils::read_package_json(&path).unwrap();
+    let pkg = utils::read_package_json(&path).unwrap_pretty();
     assert_eq!(pkg.name, "wasm-pack");
     assert_eq!(pkg.repository.ty, "git");
     assert_eq!(
@@ -42,28 +44,48 @@ fn it_creates_a_package_json_default_path() {
     );
     assert_eq!(pkg.files, ["wasm_pack_bg.wasm"]);
     assert_eq!(pkg.main, "wasm_pack.js");
+    assert!(pkg.dependencies.is_none());
 }
 
 #[test]
 fn it_creates_a_package_json_provided_path() {
     let path = "tests/fixtures/js-hello-world".to_string();
-    wasm_pack::command::create_pkg_dir(&path).unwrap();
+    wasm_pack::command::create_pkg_dir(&path).unwrap_pretty();
+    utils::mock_wasm(path.as_ref(), "js_hello_world");
     assert!(manifest::write_package_json(&path, None).is_ok());
     let package_json_path = format!("{}/pkg/package.json", &path);
     assert!(fs::metadata(package_json_path).is_ok());
     assert!(utils::read_package_json(&path).is_ok());
-    let pkg = utils::read_package_json(&path).unwrap();
+    let pkg = utils::read_package_json(&path).unwrap_pretty();
     assert_eq!(pkg.name, "js-hello-world");
 }
 
 #[test]
 fn it_creates_a_package_json_provided_path_with_scope() {
     let path = "tests/fixtures/scopes".to_string();
-    wasm_pack::command::create_pkg_dir(&path).unwrap();
-    assert!(manifest::write_package_json(&path, Some("test".to_string())).is_ok());
+    wasm_pack::command::create_pkg_dir(&path).unwrap_pretty();
+    utils::mock_wasm(path.as_ref(), "scopes_hello_world");
+    manifest::write_package_json(&path, Some("test".to_string())).unwrap_pretty();
     let package_json_path = format!("{}/pkg/package.json", &path);
     assert!(fs::metadata(package_json_path).is_ok());
     assert!(utils::read_package_json(&path).is_ok());
-    let pkg = utils::read_package_json(&path).unwrap();
+    let pkg = utils::read_package_json(&path).unwrap_pretty();
     assert_eq!(pkg.name, "@test/scopes-hello-world");
 }
+
+#[test]
+fn it_creates_package_json_with_dependencies() {
+    let path = "tests/fixtures/dependencies".to_string();
+    wasm_pack::command::create_pkg_dir(&path).unwrap_pretty();
+    utils::mock_wasm_with_deps(path.as_ref(), "dependencies");
+    manifest::write_package_json(&path, None).unwrap_pretty();
+    let package_json_path = format!("{}/pkg/package.json", &path);
+    assert!(fs::metadata(package_json_path).is_ok());
+    assert!(utils::read_package_json(&path).is_ok());
+    let pkg = utils::read_package_json(&path).unwrap_pretty();
+    let deps = pkg.dependencies.as_ref().unwrap();
+    assert_eq!(deps.len(), 1);
+    let (k, v) = deps.iter().next().unwrap();
+    assert_eq!(k, "foo");
+    assert_eq!(v, "^1.0.2");
+}
diff --git a/tests/manifest/utils.rs b/tests/manifest/utils.rs
index aa97d98d..cad11d2f 100644
--- a/tests/manifest/utils.rs
+++ b/tests/manifest/utils.rs
@@ -1,9 +1,26 @@
+use std::collections::BTreeMap;
 use std::fs::File;
 use std::io::prelude::*;
+use std::path::Path;
 
 use failure::Error;
 use serde_json;
 
+pub trait FailureExt<T> {
+    fn unwrap_pretty(self) -> T;
+}
+
+impl<T> FailureExt<T> for Result<T, Error> {
+    fn unwrap_pretty(self) -> T {
+        self.unwrap_or_else(|e| {
+            for e in e.causes() {
+                println!("err: {}", e);
+            }
+            panic!("unwrap failed");
+        })
+    }
+}
+
 #[derive(Deserialize)]
 pub struct NpmPackage {
     pub name: String,
@@ -13,6 +30,7 @@ pub struct NpmPackage {
     pub repository: Repository,
     pub files: Vec<String>,
     pub main: String,
+    pub dependencies: Option<BTreeMap<String, String>>,
 }
 
 #[derive(Deserialize)]
@@ -30,3 +48,17 @@ pub fn read_package_json(path: &str) -> Result<NpmPackage, Error> {
 
     Ok(serde_json::from_str(&pkg_contents)?)
 }
+
+const WASM: &[u8] = include_bytes!("add.wasm");
+
+pub fn mock_wasm(path: &Path, name: &str) {
+    let path = path.join("pkg").join(format!("{}_bg.wasm", name));
+    File::create(&path).unwrap().write_all(WASM).unwrap();
+}
+
+const DEP_WASM: &[u8] = include_bytes!("dependencies.wasm");
+
+pub fn mock_wasm_with_deps(path: &Path, name: &str) {
+    let path = path.join("pkg").join(format!("{}_bg.wasm", name));
+    File::create(&path).unwrap().write_all(DEP_WASM).unwrap();
+}