diff --git a/Lib/subprocess.py b/Lib/subprocess.py
index 8d0204e25d8..9e326fbea42 100644
--- a/Lib/subprocess.py
+++ b/Lib/subprocess.py
@@ -504,6 +504,9 @@ def __init__(self, args, bufsize=0, executable=None,
         """Create new Popen instance."""
         _cleanup()
 
+        if not isinstance(bufsize, (int, long)):
+            raise TypeError("bufsize must be an integer")
+
         if mswindows:
             if preexec_fn is not None:
                 raise ValueError("preexec_fn is not supported on Windows "
diff --git a/Lib/test/test_subprocess.py b/Lib/test/test_subprocess.py
index 9f7184f057f..b26d40cb29d 100644
--- a/Lib/test/test_subprocess.py
+++ b/Lib/test/test_subprocess.py
@@ -394,6 +394,17 @@ def test_wait(self):
         # Subsequent invocations should just return the returncode
         self.assertEqual(p.wait(), 0)
 
+
+    def test_invalid_bufsize(self):
+        # an invalid type of the bufsize argument should raise
+        # TypeError.
+        try:
+            subprocess.Popen([sys.executable, "-c", "pass"], "orange")
+        except TypeError:
+            pass
+        else:
+            self.fail("Expected TypeError")
+
     #
     # POSIX tests
     #