diff --git a/ChangeLog b/ChangeLog
index 7f79bfc25e..e0763c7fa3 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Tue Nov 27 13:59:29 2012  Narihiro Nakamura  <authornari@gmail.com>
+
+	* NEWS: add improvements of the garbage collector.
+
 Tue Nov 27 13:27:46 2012  Eric Hodel  <drbrain@segment7.net>
 
 	* lib/rdoc*:  Updated to RDoc 4.0 (pre-release)
diff --git a/NEWS b/NEWS
index 267c52db19..987f45017f 100644
--- a/NEWS
+++ b/NEWS
@@ -50,6 +50,12 @@ with all sufficient information, see the ChangeLog file.
       * File.fnmatch? now expands braces in the pattern if
         File::FNM_EXTGLOB option is given.
 
+  * GC
+    * improvements:
+      * introduced the bitmap marking which suppresses to copy a memory page
+        with Copy-on-Write.
+      * introduced the non-recurcive marking which avoids unexpected stack overflow.
+
   * GC::Profiler
     * added method:
       * added GC::Profiler.raw_data which returns raw profile data for GC.