diff --git a/lib/http/cookie.rb b/lib/http/cookie.rb
index f78c4bc..9dd4209 100644
--- a/lib/http/cookie.rb
+++ b/lib/http/cookie.rb
@@ -56,7 +56,9 @@ class HTTP::Cookie
     for_domain = false
     attr_hash.each_pair { |key, val|
       skey = key.to_s.downcase
-      skey.sub!(/[!?]\z/, '')
+      if skey.sub!(/\?\z/, '')
+        val = val ? true : false
+      end
       case skey
       when 'for_domain'
         for_domain = !!val
diff --git a/test/test_http_cookie.rb b/test/test_http_cookie.rb
index c24bcba..1b9bc3d 100644
--- a/test/test_http_cookie.rb
+++ b/test/test_http_cookie.rb
@@ -455,6 +455,13 @@ class TestHTTPCookie < Test::Unit::TestCase
     assert_equal 'key', cookie.name
     assert_equal 'value', cookie.value
     assert_equal expires, cookie.expires
+
+    cookie = HTTP::Cookie.new(:value => 'value', :name => 'key', :expires => expires.dup, :domain => 'example.org', :for_domain? => true)
+    assert_equal 'key', cookie.name
+    assert_equal 'value', cookie.value
+    assert_equal expires, cookie.expires
+    assert_equal 'example.org', cookie.domain
+    assert_equal true, cookie.for_domain?
   end
 
   def test_domain=