diff --git a/Gemfile b/Gemfile
index fefa2cf..0577e70 100644
--- a/Gemfile
+++ b/Gemfile
@@ -9,5 +9,6 @@ group :development, :test do
   gem 'coveralls', require: false, platforms: [:mri]
 
   gem 'activerecord', '~> 4.1'
+  gem 'nokogiri', '~> 1.6'
   gem 'ox', '>= 2.1.2', platforms: [:mri, :rbx]
 end
diff --git a/README.md b/README.md
index 50a66b7..a357acd 100644
--- a/README.md
+++ b/README.md
@@ -28,30 +28,20 @@ $ bundle
 
 ## Usage
 
-To use **Nokogiri** as a SAX handler:
+SAX Machine can use either `nokogiri` or `ox` as XML SAX handler.
 
-```ruby
-require 'sax-machine'
-```
-
-To use **Ox** as a SAX handler:
-
-Add this line to your application's Gemfile:
+To use **Nokogiri** add this line to your Gemfile:
 
 ```ruby
-gem 'ox', '>= 2.1.2'
+gem 'nokogiri', '~> 1.6'
 ```
 
-Tell SAXMachine to use Ox:
+To use **Ox** add this line to your Gemfile:
 
 ```ruby
-require 'sax-machine'
-SAXMachine.handler = :ox
+gem 'ox', '>= 2.1.2'
 ```
 
-Please note that this operation is not thread-safe, so it's better to define
-handler at initialization stage and do not change it during runtime.
-
 ## Examples
 
 Include `SAXMachine` in any class and define properties to parse:
diff --git a/lib/sax-machine.rb b/lib/sax-machine.rb
index 64fa824..5bfa244 100644
--- a/lib/sax-machine.rb
+++ b/lib/sax-machine.rb
@@ -14,4 +14,8 @@ def self.handler=(handler)
   end
 end
 
-SAXMachine.handler = :nokogiri
+begin
+  SAXMachine.handler = :ox
+rescue LoadError
+  SAXMachine.handler = :nokogiri
+end
diff --git a/sax-machine.gemspec b/sax-machine.gemspec
index 6d603f6..44e4f67 100644
--- a/sax-machine.gemspec
+++ b/sax-machine.gemspec
@@ -16,6 +16,5 @@ Gem::Specification.new do |s|
   s.require_paths = ["lib"]
   s.platform      = Gem::Platform::RUBY
 
-  s.add_dependency "nokogiri", "~> 1.6.0"
   s.add_development_dependency "rspec", "~> 3.0"
 end
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 546a9d0..91d44dc 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -14,9 +14,7 @@
 end
 
 require File.expand_path(File.dirname(__FILE__) + '/../lib/sax-machine')
-if ENV['HANDLER'] == 'ox'
-  SAXMachine.handler = :ox
-end
+SAXMachine.handler = ENV['HANDLER'].to_sym
 
 RSpec.configure do |config|
   config.run_all_when_everything_filtered = true