diff --git a/ChangeLog b/ChangeLog
index 0ca9b0dc93..773be8af70 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+Thu Dec  7 09:29:02 2006  Yukihiro Matsumoto  <matz@ruby-lang.org>
+
+	* lib/weakref.rb (WeakRef::__setobj__): should support
+	  marshaling.  [ruby-talk:228508]
+
+	* lib/delegate.rb (Delegator::marshal_load): need to call
+	  __setobj__.
+
 Wed Dec  6 23:56:14 2006  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* Makefile.in, common.mk (NULLCMD): moved for platforms that empty
diff --git a/lib/delegate.rb b/lib/delegate.rb
index 93c9803a18..d810ccad42 100644
--- a/lib/delegate.rb
+++ b/lib/delegate.rb
@@ -184,6 +184,7 @@ class Delegator
   # Reinitializes delegation from a serialized object.
   def marshal_load(obj)
     initialize_methods(obj)
+    __setobj__(obj)
   end
 end
 
diff --git a/lib/weakref.rb b/lib/weakref.rb
index 7d43f71264..591819c948 100644
--- a/lib/weakref.rb
+++ b/lib/weakref.rb
@@ -48,18 +48,7 @@ class WeakRef<Delegator
   # Create a new WeakRef from +orig+.
   def initialize(orig)
     super
-    @__id = orig.__id__
-    ObjectSpace.define_finalizer orig, @@final
-    ObjectSpace.define_finalizer self, @@final
-    __old_status = Thread.critical
-    begin
-      Thread.critical = true
-      @@id_map[@__id] = [] unless @@id_map[@__id]
-    ensure
-      Thread.critical = __old_status
-    end
-    @@id_map[@__id].push self.__id__
-    @@id_rev_map[self.__id__] = @__id
+    __setobj__(orig)
   end
 
   # Return the object this WeakRef references. Raises RefError if the object
@@ -76,6 +65,23 @@ class WeakRef<Delegator
     end
   end
 
+  def __setobj__(obj)
+    @__id = obj.__id__
+    __old_status = Thread.critical
+    begin
+      Thread.critical = true
+      unless @@id_rev_map.key?(self)
+        ObjectSpace.define_finalizer obj, @@final
+        ObjectSpace.define_finalizer self, @@final
+      end
+      @@id_map[@__id] = [] unless @@id_map[@__id]
+    ensure
+      Thread.critical = __old_status
+    end
+    @@id_map[@__id].push self.__id__
+    @@id_rev_map[self.__id__] = @__id
+  end
+
   # Returns true if the referenced object still exists, and false if it has
   # been garbage collected.
   def weakref_alive?