diff --git a/netlib/http/request.py b/netlib/http/request.py
index 01801d429..b64ccc51a 100644
--- a/netlib/http/request.py
+++ b/netlib/http/request.py
@@ -28,7 +28,7 @@ class RequestData(message.MessageData):
 
         self.first_line_format = first_line_format
         self.method = method
-        self.scheme = scheme
+        self.scheme = scheme or b''
         self.host = host
         self.port = port
         self.path = path