diff --git a/ChangeLog b/ChangeLog
index b85d56e83e..edf878b224 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Mon Aug 23 00:23:07 2010  Tadayoshi Funaba  <tadf@dotrb.org>
+
+	* lib/date.rb, lib/date/format.rb: [ruby-core:31695]
+
 Sun Aug 22 09:08:02 2010  Tanaka Akira  <akr@fsij.org>
 
 	* include/ruby/ruby.h (UINT2NUM): fix ifdef condition for LLP64.
diff --git a/lib/date.rb b/lib/date.rb
index 5295ce9b7f..8b1796201c 100644
--- a/lib/date.rb
+++ b/lib/date.rb
@@ -1738,11 +1738,6 @@ class DateTime < Date
     new_by_frags(elem, sg)
   end
 
-  def self.rfc3339(str='-4712-01-01T00:00:00+00:00', sg=ITALY) # :nodoc:
-    elem = _rfc3339(str)
-    new_by_frags(elem, sg)
-  end
-
   def self.xmlschema(str='-4712-01-01T00:00:00+00:00', sg=ITALY) # :nodoc:
     elem = _xmlschema(str)
     new_by_frags(elem, sg)
diff --git a/lib/date/format.rb b/lib/date/format.rb
index 1a420fb398..6894e945e3 100644
--- a/lib/date/format.rb
+++ b/lib/date/format.rb
@@ -342,7 +342,7 @@ class Date
 
   def iso8601() strftime('%F') end
 
-  def rfc3339() iso8601 end
+  def rfc3339() strftime('%FT%T%:z') end
 
   def xmlschema() iso8601 end # :nodoc:
 
diff --git a/test/date/test_date_strftime.rb b/test/date/test_date_strftime.rb
index 117517256c..e4ab3550b3 100644
--- a/test/date/test_date_strftime.rb
+++ b/test/date/test_date_strftime.rb
@@ -332,7 +332,6 @@ class TestDateStrftime < Test::Unit::TestCase
     assert_equal(d.ctime, d.asctime)
 
     assert_equal('2001-02-03', d.iso8601)
-    assert_equal(d.rfc3339, d.iso8601)
     assert_equal(d.xmlschema, d.iso8601)
     assert_equal('Sat, 3 Feb 2001 00:00:00 +0000', d.rfc2822)
     assert_equal(d.rfc822, d.rfc2822)