diff --git a/ChangeLog b/ChangeLog
index e05c0db7e0..5922574536 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Sat Aug 23 15:14:10 2008  Koichi Sasada  <ko1@atdot.net>
+
+	* vm_opts.h: enable "OPT_TRACE_INSTRUCTION" on default.
+
 Sat Aug 23 14:59:32 2008  Tanaka Akira  <akr@fsij.org>
 
 	* include/ruby/encoding.h (ECONV_INVALID_MASK): defined.
diff --git a/vm_opts.h b/vm_opts.h
index 2bb9ee6bb0..9e357f4c40 100644
--- a/vm_opts.h
+++ b/vm_opts.h
@@ -18,7 +18,7 @@
  * Following definitions are default values.
  */
 
-#define OPT_TRACE_INSTRUCTION        0
+#define OPT_TRACE_INSTRUCTION        1
 #define OPT_TAILCALL_OPTIMIZATION    0
 #define OPT_PEEPHOLE_OPTIMIZATION    1
 #define OPT_SPECIALISED_INSTRUCTION  1