diff -r 0b97ba8a1410447797c0a1d049b2cfb6cc066ff3 lib/sqlalchemy/cextension/resultproxy.c
--- a/lib/sqlalchemy/cextension/resultproxy.c	Wed Mar 14 13:10:31 2012 -0700
+++ b/lib/sqlalchemy/cextension/resultproxy.c	Wed Mar 14 13:47:15 2012 -0700
@@ -353,7 +353,16 @@
     else
         return tmp;
 
-    return BaseRowProxy_subscript(self, name);
+    tmp = BaseRowProxy_subscript(self, name);
+    if (PyErr_ExceptionMatches(PyExc_KeyError)) {
+        PyErr_Format(
+                PyExc_AttributeError, 
+                "Could not locate column in row for column '%s'",
+                PyString_AsString(name)
+            );
+        return NULL;
+    }
+    return tmp;
 }
 
 /***********************