diff --git a/lib/faraday/cookie_jar.rb b/lib/faraday/cookie_jar.rb
index 6b6f0cc..428f79f 100644
--- a/lib/faraday/cookie_jar.rb
+++ b/lib/faraday/cookie_jar.rb
@@ -11,7 +11,12 @@ def initialize(app, options = {})
     def call(env)
       cookies = @jar.cookies(env[:url])
       unless cookies.empty?
-        env[:request_headers]["Cookie"] = HTTP::Cookie.cookie_value(cookies)
+        cookie_value = HTTP::Cookie.cookie_value(cookies)
+        if env[:request_headers]["Cookie"]
+          env[:request_headers]["Cookie"] = cookie_value + ';' + env[:request_headers]["Cookie"]
+        else
+          env[:request_headers]["Cookie"] = cookie_value
+        end
       end
 
       @app.call(env).on_complete do |res|
@@ -27,4 +32,4 @@ def call(env)
 
 if Faraday.respond_to? :register_middleware
   Faraday.register_middleware :cookie_jar => lambda { Faraday::CookieJar }
-end
+end
\ No newline at end of file
diff --git a/spec/faraday-cookie_jar/cookie_jar_spec.rb b/spec/faraday-cookie_jar/cookie_jar_spec.rb
index 1330f87..b5d2ce0 100644
--- a/spec/faraday-cookie_jar/cookie_jar_spec.rb
+++ b/spec/faraday-cookie_jar/cookie_jar_spec.rb
@@ -24,5 +24,16 @@
     sleep 2
     conn.get('/dump').body.should_not == 'foo=bar'
   end
+
+  it 'multiple cookies' do
+    conn.get('/default')
+
+    response = conn.send('get') do |request|
+      request.url '/multiple_cookies'
+      request.headers.merge!({:Cookie => 'language=english'})
+    end
+
+    response.body.should == 'foo=bar;language=english'
+  end
 end
 
diff --git a/spec/support/fake_app.rb b/spec/support/fake_app.rb
index 3704065..638a6d6 100644
--- a/spec/support/fake_app.rb
+++ b/spec/support/fake_app.rb
@@ -16,4 +16,8 @@ class FakeApp < Sinatra::Application
   get '/expires' do
     response.set_cookie "foo", :value => "bar", :expires => Time.now + 1
   end
+
+  get '/multiple_cookies' do
+    "foo=#{request.cookies['foo']};language=#{request.cookies['language']}"
+  end
 end