diff --git a/lib/index.js b/lib/index.js
index aaad905..b95b3f6 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -3,7 +3,7 @@ var Babel = require('babel-core');
 var internals = {};
 internals.transform = function (content, filename) {
 
-    if (/^node_modules/.test(filename)) {
+    if (/(^|\/)node_modules/.test(filename)) {
         return content;
     }