diff --git a/ChangeLog b/ChangeLog
index 8b996fac28..88d1d17203 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Mon Sep 25 08:11:35 2006  Yukihiro Matsumoto  <matz@ruby-lang.org>
+
+	* random.c (rb_f_rand): RDoc typo fix.  a patch from Frederick
+	  Cheung <fred at 82ask.com>.  [ruby-talk:216047]
+
 Sun Sep 24 21:19:24 2006  Guy Decoux  <ts@moulon.inra.fr>
 
 	* gc.c (gc_mark_children): NODE_POSTEXE holds Ruby VALUE.
diff --git a/random.c b/random.c
index 2d335d13f8..8dad78a274 100644
--- a/random.c
+++ b/random.c
@@ -419,7 +419,7 @@ limited_big_rand(struct RBignum *limit)
  *  than or equal to zero and less than max1. <code>Kernel::srand</code>
  *  may be used to ensure repeatable sequences of random numbers between
  *  different runs of the program. Ruby currently uses a modified
- *  Mersenne Twister with a period of 219937-1.
+ *  Mersenne Twister with a period of 2**19937-1.
  *     
  *     srand 1234                 #=> 0
  *     [ rand,  rand ]            #=> [0.191519450163469, 0.49766366626136]