diff --git a/loopy/codegen/__init__.py b/loopy/codegen/__init__.py
index ac169d5d692e02d3885b493bd94b413580bca2ea..371dd950d9f793dc4cee4473a34273de4618d9b8 100644
--- a/loopy/codegen/__init__.py
+++ b/loopy/codegen/__init__.py
@@ -338,7 +338,7 @@ def generate_code(kernel, with_annotation=False,
 
     for arg in kernel.args:
         seen_dtypes.add(arg.dtype)
-    for tv in kernel.temporary_variables:
+    for tv in kernel.temporary_variables.itervalues():
         seen_dtypes.add(tv.dtype)
 
     preambles = kernel.preambles[:]