diff --git a/Lib/subprocess.py b/Lib/subprocess.py
index ea1e0d1..8b25c2f 100644
--- a/Lib/subprocess.py
+++ b/Lib/subprocess.py
@@ -499,7 +499,7 @@
         if result:
             result.append(' ')
 
-        needquote = (" " in arg) or ("\t" in arg)
+        needquote = (" " in arg) or ("\t" in arg) or arg == ""
         if needquote:
             result.append('"')