diff --git a/lib/restclient/payload.rb b/lib/restclient/payload.rb
index 518bdd4..a036139 100644
--- a/lib/restclient/payload.rb
+++ b/lib/restclient/payload.rb
@@ -147,12 +147,17 @@ module RestClient
 
       # for UrlEncoded escape the keys
       def handle_key key
-        URI.escape(key.to_s, Regexp.new("[^#{URI::PATTERN::UNRESERVED}]"))
+        parser.escape(key.to_s, Regexp.new("[^#{URI::PATTERN::UNRESERVED}]"))
       end
 
       def headers
         super.merge({'Content-Type' => 'application/x-www-form-urlencoded'})
       end
+
+      private
+        def parser
+          URI.const_defined?(:Parser) ? URI::Parser.new : URI
+        end
     end
 
     class Multipart < Base
diff --git a/lib/restclient/request.rb b/lib/restclient/request.rb
index 56802b3..fe05fbc 100644
--- a/lib/restclient/request.rb
+++ b/lib/restclient/request.rb
@@ -137,7 +137,7 @@ module RestClient
           if p[k].is_a? Hash
             process_payload(p[k], key)
           else
-            value = URI.escape(p[k].to_s, Regexp.new("[^#{URI::PATTERN::UNRESERVED}]"))
+            value = parser.escape(p[k].to_s, Regexp.new("[^#{URI::PATTERN::UNRESERVED}]"))
             "#{key}=#{value}"
           end
         end.join("&")
@@ -312,6 +312,11 @@ module RestClient
       {:accept => '*/*; q=0.5, application/xml', :accept_encoding => 'gzip, deflate'}
     end
 
+    private
+      def parser
+        URI.const_defined?(:Parser) ? URI::Parser.new : URI
+      end
+
   end
 end