diff --git a/lib/contracts/compiler.js b/lib/contracts/compiler.js
index e6c4fc23e..75ce08f95 100644
--- a/lib/contracts/compiler.js
+++ b/lib/contracts/compiler.js
@@ -16,7 +16,8 @@ class Compiler {
 
     let pluginCompilers = self.plugins.getPluginsProperty('compilers', 'compilers');
     pluginCompilers.forEach(function (compilerObject) {
-      available_compilers[compilerObject.extension] = compilerObject.cb;
+      if(available_compilers[compilerObject.extension] === undefined)
+        available_compilers[compilerObject.extension] = compilerObject.cb;
     });
 
     let compiledObject = {};