diff --git a/lib/zero/request/parameter.rb b/lib/zero/request/parameter.rb
index cac9915..a9a3abe 100644
--- a/lib/zero/request/parameter.rb
+++ b/lib/zero/request/parameter.rb
@@ -88,9 +88,7 @@ module Zero
       # @param query [String] the query string
       # @return [Hash] the key/valuie pairs
       def parse_string(query)
-        params = query.split('&')
-        params.map! {|part| part.split('=') }
-        Hash[params]
+        Hash[URI.decode_www_form(query)]
       end
     end
   end
diff --git a/spec/unit/request/parameter/payload_spec.rb b/spec/unit/request/parameter/payload_spec.rb
index df9f02d..af1d2ab 100644
--- a/spec/unit/request/parameter/payload_spec.rb
+++ b/spec/unit/request/parameter/payload_spec.rb
@@ -3,17 +3,17 @@ require 'spec_helper'
 describe Zero::Request::Parameter, '#payload' do
   subject { Zero::Request::Parameter.new(env) }
 
-  context "without parameters" do
+  context 'without parameters' do
     let(:env) { EnvGenerator.get('/foo') }
     its(:payload) { should == {} }
   end
 
-  context "with a query string" do
+  context 'with a query string' do
     let(:env) { EnvGenerator.get('/foo?bar=baz') }
     its(:payload) { should == {} }
   end
 
-  context "with a post body" do
+  context 'with a post body' do
     let(:env) do
       EnvGenerator.post('/foo', {
         :input => 'bar=baz', 'CONTENT_TYPE' => 'multipart/form-data'
@@ -21,4 +21,13 @@ describe Zero::Request::Parameter, '#payload' do
     end
     its(:payload) { should == {'bar' => 'baz'} }
   end
+
+  context 'with special characters' do
+    let(:env) do
+      EnvGenerator.post('/foo', {
+        :input => 'bar=foo%20bar', 'CONTENT_TYPE' => 'multipart/form-data'
+      })
+    end
+    its(:payload) { should == {'bar' => 'foo bar'} }
+  end
 end
diff --git a/spec/unit/request/parameter/query_spec.rb b/spec/unit/request/parameter/query_spec.rb
index 5a3964b..940e80e 100644
--- a/spec/unit/request/parameter/query_spec.rb
+++ b/spec/unit/request/parameter/query_spec.rb
@@ -3,18 +3,23 @@ require 'spec_helper'
 describe Zero::Request::Parameter, '#query' do
   subject { Zero::Request::Parameter.new(env) }
 
-  context "without parameters" do
+  context 'without parameters' do
     let(:env) { EnvGenerator.get('/foo') }
     its(:query) { should == {} }
   end
 
-  context "with a query string" do
+  context 'with a query string' do
     let(:env) { EnvGenerator.get('/foo?bar=baz') }
     its(:query) { should == {'bar' => 'baz'} }
   end
 
-  context "with a post body" do
+  context 'with a post body' do
     let(:env) { EnvGenerator.post('/foo', {:input => 'bar=baz'}) }
     its(:query) { should == {} }
   end
+
+  context 'with special characters' do
+    let(:env) { EnvGenerator.get('/foo?bar=foo%20bar') }
+    its(:query) { should == {'bar' => 'foo bar'} }
+  end
 end