diff --git a/lib/preprocessor.js b/lib/preprocessor.js
index 76caaa02f..18b367da9 100644
--- a/lib/preprocessor.js
+++ b/lib/preprocessor.js
@@ -60,7 +60,7 @@ var createPreprocessor = function(config, basePath, injector) {
     });
 
     return fs.readFile(file.originalPath, function(err, buffer) {
-      nextPreprocessor(buffer.toString());
+      nextPreprocessor(buffer);
     });
   };
 };