diff --git a/requests/models.py b/requests/models.py
index f001c08b..8a293cb9 100644
--- a/requests/models.py
+++ b/requests/models.py
@@ -752,7 +752,8 @@ class Response(object):
 
         # Try to fall back:
         try:
-            content = unicode(content, encoding, errors='replace')
+            if not content:
+                content = unicode(content, encoding, errors='replace')
         except UnicodeError, TypeError:
             pass