diff --git a/ChangeLog b/ChangeLog
index b59d440f6a..538d2dfcac 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Thu Jan 14 20:01:00 2016  NARUSE, Yui  <naruse@ruby-lang.org>
+
+	* lib/uri/generic.rb (URI::Generic#to_s): change encoding to
+	  UTF-8 as Ruby 2.2/ by Koichi ITO <koic.ito@gmail.com>
+	  https://github.com/ruby/ruby/pull/1188 fix GH-1188
+
 Thu Jan 14 17:36:16 2016  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* variable.c (rb_f_global_variables): add matched back references
diff --git a/lib/uri/generic.rb b/lib/uri/generic.rb
index 224a16317b..aba54c14b6 100644
--- a/lib/uri/generic.rb
+++ b/lib/uri/generic.rb
@@ -1341,7 +1341,7 @@ module URI
     # Constructs String from URI
     #
     def to_s
-      str = String.new
+      str = ''.dup
       if @scheme
         str << @scheme
         str << ':'
diff --git a/test/uri/test_generic.rb b/test/uri/test_generic.rb
index eda6497da2..a427809daf 100644
--- a/test/uri/test_generic.rb
+++ b/test/uri/test_generic.rb
@@ -768,6 +768,7 @@ class URI::TestGeneric < Test::Unit::TestCase
   def test_build
     u = URI::Generic.build(['http', nil, 'example.com', 80, nil, '/foo', nil, nil, nil])
     assert_equal('http://example.com:80/foo', u.to_s)
+    assert_equal(Encoding::UTF_8, u.to_s.encoding)
 
     u = URI::Generic.build(:port => "5432")
     assert_equal(":5432", u.to_s)