diff --git a/ChangeLog b/ChangeLog
index da5d1417e3..9070a588aa 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Sat Feb 23 10:17:00 2013  Zachary Scott  <zachary@zacharyscott.net>
+
+	* object.c (rb_obj_comp): Documenting Object#<=> return values
+	  Patch by Stefan Rusterholz
+
 Sat Feb 23 09:48:41 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* dir.c (file_s_fnmatch, fnmatch_brace): encoding-incompatible pattern
diff --git a/object.c b/object.c
index ceee4d47eb..76ff316543 100644
--- a/object.c
+++ b/object.c
@@ -1320,6 +1320,17 @@ rb_obj_not_match(VALUE obj1, VALUE obj2)
  *     obj <=> other -> 0 or nil
  *
  *  Returns 0 if obj === other, otherwise nil.
+ *
+ *  The <=> is used by various methods to compare objects, for example
+ *  Enumerable#sort, Enumerable#max etc.
+ *
+ *  Your implementation of <=> should return one of the following values: -1, 0,
+ *  1 or nil. -1 means self is smaller than other. 0 means self is equal to other.
+ *  1 means self is bigger than other. Nil means the two values could not be
+ *  compared.
+ *
+ *  When you defined <=>, you can include Comparable to gain the methods <=, <,
+ *  ==, >=, > and between?.
  */
 static VALUE
 rb_obj_cmp(VALUE obj1, VALUE obj2)