diff --git a/lib/sofa.rb b/lib/sofa.rb
index 363158b..d3cb9cd 100644
--- a/lib/sofa.rb
+++ b/lib/sofa.rb
@@ -1,3 +1,5 @@
+require 'crack'
+
 module Sofa
   autoload :Version, 'sofa/version'
   autoload :Mapping, 'sofa/mapping'
diff --git a/sofa.gemspec b/sofa.gemspec
index 8da2c1d..90607f5 100644
--- a/sofa.gemspec
+++ b/sofa.gemspec
@@ -39,6 +39,7 @@ Gem::Specification.new do |s|
 
     if Gem::Version.new(Gem::RubyGemsVersion) >= Gem::Version.new('1.2.0') then
       s.add_runtime_dependency(%q<httparty>, [">= 0"])
+      s.add_runtime_dependency(%q<crack>, [">= 0"])
       s.add_development_dependency(%q<rspec>, [">= 1.2.9"])
       s.add_development_dependency(%q<mocha>, [">= 0"])
       s.add_development_dependency(%q<fakeweb>, [">= 0"])