diff --git a/src/index.js b/src/index.js
index 0242a62..7a68e27 100644
--- a/src/index.js
+++ b/src/index.js
@@ -45,8 +45,9 @@ class Dotenv {
       target,
       version
     })
+    const DefinePlugin = (compiler.webpack && compiler.webpack.DefinePlugin) || require('webpack').DefinePlugin
 
-    new compiler.webpack.DefinePlugin(data).apply(compiler)
+    new DefinePlugin(data).apply(compiler)
   }
 
   gatherVariables () {