diff --git a/ChangeLog b/ChangeLog
index 8ee0fe1b93..d6ae3228d8 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Wed Sep 29 12:31:12 2010  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* lib/rdoc/known_classes.rb (RDoc::KNOWN_CLASSES): add Encoding.
+
 Tue Sep 28 20:50:23 2010  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* tool/config.sub (x64): regularize same as mswin.
diff --git a/lib/rdoc/known_classes.rb b/lib/rdoc/known_classes.rb
index 720a35f497..eb90185f53 100644
--- a/lib/rdoc/known_classes.rb
+++ b/lib/rdoc/known_classes.rb
@@ -10,6 +10,7 @@ module RDoc
     "rb_cClass"            => "Class",
     "rb_cData"             => "Data",
     "rb_cDir"              => "Dir",
+    "rb_cEncoding"         => "Encoding",
     "rb_cFalseClass"       => "FalseClass",
     "rb_cFile"             => "File",
     "rb_cFixnum"           => "Fixnum",