diff --git a/lib/sinatra.rb b/lib/sinatra.rb
index eb7c18d3..c68f0156 100644
--- a/lib/sinatra.rb
+++ b/lib/sinatra.rb
@@ -160,10 +160,13 @@ module Sinatra
         
     def invoke(request)
       params = {}
-      if options[:agent] 
-        return unless request.user_agent =~ options[:agent]
+      if agent = options[:agent] 
+        return unless request.user_agent =~ agent
         params[:agent] = $~[1..-1]
       end
+      if host = options[:host] 
+        return unless host === request.host
+      end
       return unless pattern =~ request.path_info.squeeze('/')
       params.merge!(param_keys.zip($~.captures.map(&:from_param)).to_hash)
       Result.new(block, params, 200)
diff --git a/test/diddy_test.rb b/test/diddy_test.rb
new file mode 100644
index 00000000..a6a1cfbe
--- /dev/null
+++ b/test/diddy_test.rb
@@ -0,0 +1,41 @@
+require File.dirname(__FILE__) + '/helper'
+
+context "Diddy" do
+
+  setup do
+    Sinatra.application = nil
+  end
+
+  specify "should map urls to different apps" do
+
+    get '/' do
+      'asdf'
+    end
+    
+    get_it '/'
+    assert ok?
+    assert_equal('asdf', body)
+    
+    get '/foo', :host => 'foo.sinatrarb.com' do
+      'in foo!'
+    end
+
+    get '/foo', :host => 'bar.sinatrarb.com'  do
+      'in bar!'
+    end
+    
+    get_it '/foo', {}, 'HTTP_HOST' => 'foo.sinatrarb.com'
+    assert ok?
+    assert_equal 'in foo!', body
+
+    get_it '/foo', {}, 'HTTP_HOST' => 'bar.sinatrarb.com'
+    assert ok?
+    assert_equal 'in bar!', body
+    
+    get_it '/foo'
+    assert not_found?
+    
+  end
+
+end
+