diff --git a/bson/__init__.py b/bson/__init__.py
index e8d66d4a2..c68892247 100644
--- a/bson/__init__.py
+++ b/bson/__init__.py
@@ -535,7 +535,7 @@ def decode_all(data, as_class=dict,
     except Exception:
         # Change exception type to InvalidBSON but preserve traceback.
         exc_type, exc_value, exc_tb = sys.exc_info()
-        raise InvalidBSON, InvalidBSON(str(exc_value)), exc_tb
+        raise InvalidBSON, str(exc_value), exc_tb
 if _use_c:
     decode_all = _cbson.decode_all