diff --git a/ChangeLog b/ChangeLog
index 6e2be88a6c..7e6692d27e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Sun Aug  6 20:34:24 2006  Tadayoshi Funaba  <tadf@dotrb.org>
+
+	* lib/date/format.rb (str[fp]time): %[EO]U didn't denote %U.
+
 Sun Aug  6 17:12:12 2006  Tanaka Akira  <akr@fsij.org>
 
 	* io.c (io_reopen): STDERR.reopen(open("/dev/tty", "w")) should not
diff --git a/lib/date/format.rb b/lib/date/format.rb
index 04fadd84a2..4425635d33 100644
--- a/lib/date/format.rb
+++ b/lib/date/format.rb
@@ -148,7 +148,7 @@ class Date
 	return unless str.sub!(/\A(\d+)/o, '')
 	val = $1.to_i
 	return unless (0..53) === val
-	elem[if c == '%U' then :wnum0 else :wnum1 end] = val
+	elem[if c[-1,1] == 'U' then :wnum0 else :wnum1 end] = val
       when '%u'
 	return unless str.sub!(/\A(\d+)/o, '')
 	val = $1.to_i
@@ -533,7 +533,7 @@ class Date
       when '%t'; o << "\t"					# P2,ID
       when '%U', '%W'
 	a = self.class.civil_to_jd(year, 1, 1, ns?) + 6
-	k = if c == '%U' then 0 else 1 end
+	k = if c[-1,1] == 'U' then 0 else 1 end
 	w = (jd - (a - ((a - k) + 1) % 7) + 7) / 7
 	o << '%02d' % w
       when '%u'; o <<   '%d' % cwday				# P2,ID