diff --git a/actionpack/actionpack.gemspec b/actionpack/actionpack.gemspec
index 254a4e8396..8a7169bfa1 100644
--- a/actionpack/actionpack.gemspec
+++ b/actionpack/actionpack.gemspec
@@ -21,6 +21,6 @@ Gem::Specification.new do |s|
   s.add_dependency('activemodel',   '= 3.0.0.beta1')
   s.add_dependency('rack',          '~> 1.1.0')
   s.add_dependency('rack-test',     '~> 0.5.0')
-  s.add_dependency('rack-mount',    '~> 0.5.0')
+  s.add_dependency('rack-mount',    '~> 0.4.7')
   s.add_dependency('erubis',        '~> 2.6.5')
 end