diff --git a/ChangeLog b/ChangeLog
index 82b4cc4d96..1c237683ba 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Tue Jun  3 15:12:01 2008  Akinori MUSHA  <knu@iDaemons.org>
+
+	* lib/set.rb (Set#classify): Back out the `group_by' alias.
+	  Better think twice.
+
 Tue Jun  3 15:00:22 2008  Akinori MUSHA  <knu@iDaemons.org>
 
 	* lib/set.rb (Set#collect, Set#select): Back out.  I thought it
diff --git a/lib/set.rb b/lib/set.rb
index 4cba96e9e2..b6988b6c77 100644
--- a/lib/set.rb
+++ b/lib/set.rb
@@ -370,7 +370,6 @@ class Set
 
     h
   end
-  alias group_by classify
 
   # Divides the set into a set of subsets according to the commonality
   # defined by the given block.