diff --git a/README.md b/README.md
index 37f2c65..22602e7 100644
--- a/README.md
+++ b/README.md
@@ -100,10 +100,13 @@ var b = browserify('main.js')
 
 b.transform(envify({
   NODE_ENV: 'development'
-}))
+}), {global: true})
 b.bundle().pipe(output)
 ```
 
+Passing `{global: true}` as second argument is required for browserify to transform
+modules included in `node_modules`.
+
 ## Purging `process.env` ##
 
 By default, environment variables that are not defined will be left untouched.