diff --git a/GFG/Strings/Longest Even length substring.cpp b/GFG/Strings/Longest Even length substring.cpp
new file mode 100644
index 0000000..ed4d317
--- /dev/null
+++ b/GFG/Strings/Longest Even length substring.cpp	
@@ -0,0 +1,29 @@
+#include <bits/stdc++.h>
+using namespace std;
+int main()
+ {  
+    ios_base::sync_with_stdio(false); 
+    cin.tie(NULL);
+    int T;
+    cin>>T;
+    while(T--){
+        string s;
+        cin>>s;
+        int res=0;
+        int l,r,lsum=0,rsum=0;
+        for(int i=0;i<s.length();i++){
+            lsum=0, rsum=0;
+            l=i,r=i+1;
+            while(l>=0 && r<s.length()){
+                lsum+=(s[l]-'0');
+                rsum+=(s[r]-'0');
+                if(rsum==lsum)res=max(res,r-l+1);
+                l--;
+                r++;
+            }
+        }
+        cout<<res<<"\n";
+	//code
+    }
+	return 0;
+}
\ No newline at end of file