diff --git a/ChangeLog b/ChangeLog
index d68931b930..4e8bec7f2d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Thu Aug 14 17:27:07 2008  Yukihiro Matsumoto  <matz@ruby-lang.org>
+
+	* version.c (Init_version): add RUBY_ENGINE constant.
+
 Thu Aug 14 15:34:10 2008  Tanaka Akira  <akr@fsij.org>
 
 	* transcode.c (rb_econv_conv): new function.  it don't consume input
diff --git a/version.c b/version.c
index 3a1d1fc3ff..53edf02574 100644
--- a/version.c
+++ b/version.c
@@ -22,6 +22,7 @@ const char ruby_platform[] = RUBY_PLATFORM;
 const int ruby_patchlevel = RUBY_PATCHLEVEL;
 const char ruby_description[] = RUBY_DESCRIPTION;
 const char ruby_copyright[] = RUBY_COPYRIGHT;
+const char ruby_engine[] = "ruby";
 
 void
 Init_version(void)
@@ -33,6 +34,7 @@ Init_version(void)
     rb_define_global_const("RUBY_REVISION", INT2FIX(RUBY_REVISION));
     rb_define_global_const("RUBY_DESCRIPTION", MKSTR(description));
     rb_define_global_const("RUBY_COPYRIGHT", MKSTR(copyright));
+    rb_define_global_const("RUBY_ENGINE", MKSTR(engine));
 }
 
 void