diff --git a/actionpack/lib/action_view/base.rb b/actionpack/lib/action_view/base.rb
index 4840b2526d43320e9c217176154799fc7cb88386..f398756550da4fafc53d2523235ccc801182c4be 100644
--- a/actionpack/lib/action_view/base.rb
+++ b/actionpack/lib/action_view/base.rb
@@ -168,12 +168,12 @@ class Base
     # Specify whether file modification times should be checked to see if a template needs recompilation
     @@cache_template_loading = false
     cattr_accessor :cache_template_loading
-
-    # Specify whether file extension lookup should be cached, and whether template base path lookup should be cached.
-    # Should be +false+ for development environments. Defaults to +true+.
-    @@cache_template_extensions = true
-    cattr_accessor :cache_template_extensions
     
+    def self.cache_template_extensions=(*args)
+      ActiveSupport::Deprecation.warn("config.action_view.cache_template_extensions option has been deprecated and has no affect. " <<
+                                       "Please remove it from your config files.", caller)
+    end
+
     # Specify whether RJS responses should be wrapped in a try/catch block
     # that alert()s the caught exception (and then re-raises it). 
     @@debug_rjs = false