diff --git a/lib/geocoder/lookups/base.rb b/lib/geocoder/lookups/base.rb
index bc4703a275459b5501da5f43d7fc8a25d5c3969d..014abe2d37882fe56e5e83be2f929cb3d080aee9 100644
--- a/lib/geocoder/lookups/base.rb
+++ b/lib/geocoder/lookups/base.rb
@@ -99,7 +99,7 @@ module Geocoder
         protocol = "http#{'s' if configuration.use_https}"
         proxy_name = "#{protocol}_proxy"
         if proxy = configuration.send(proxy_name)
-          proxy_url = protocol + '://' + proxy
+          proxy_url = !!(proxy =~ /^#{protocol}/) ? proxy : protocol + '://' + proxy
           begin
             uri = URI.parse(proxy_url)
           rescue URI::InvalidURIError
diff --git a/test/proxy_test.rb b/test/proxy_test.rb
index 654b8160c0dd8c89fb3affbda21a8bebc423aedd..8460ee49ed464f4c8c16ce4500a58e35e8b05bf9 100644
--- a/test/proxy_test.rb
+++ b/test/proxy_test.rb
@@ -20,4 +20,17 @@ class ProxyTest < Test::Unit::TestCase
       Geocoder::Lookup::Google.new.send(:http_client)
     end
   end
+
+  def test_accepts_proxy_with_http_protocol
+    Geocoder.configure(:http_proxy => 'http://localhost')
+    lookup = Geocoder::Lookup::Google.new
+    assert lookup.send(:http_client).proxy_class?
+  end
+
+  def test_accepts_proxy_with_https_protocol
+    Geocoder.configure(:https_proxy => 'https://localhost')
+    Geocoder.configure(:use_https => true)
+    lookup = Geocoder::Lookup::Google.new
+    assert lookup.send(:http_client).proxy_class?
+  end
 end