diff --git a/iugu.gemspec b/iugu.gemspec
index 8aa1483..c8c8522 100644
--- a/iugu.gemspec
+++ b/iugu.gemspec
@@ -17,7 +17,7 @@ Gem::Specification.new do |spec|
   spec.test_files    = spec.files.grep(%r{^(test|spec|features)/})
   spec.require_paths = ['lib']
 
-  spec.add_dependency 'rest-client'
+  spec.add_dependency 'rest-client', '1.6.10'
 
   spec.add_development_dependency 'bundler', '~> 1.5'
   spec.add_development_dependency 'rake'