diff --git a/ChangeLog b/ChangeLog
index 1d7faaae34..b8ab3c74e7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Sun Oct  3 19:44:23 2010  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* configure.in (Makefile): get rid of duplicated ruby target when
+	  already there it was.
+
 Sat Oct  2 22:59:32 2010  Masaki Suketa <masaki.suketa@nifty.ne.jp>
 
 	* test/win32ole/test_thread.rb: add for win32ole with Thread.
diff --git a/configure.in b/configure.in
index 4545023687..c7d257c995 100644
--- a/configure.in
+++ b/configure.in
@@ -2746,6 +2746,7 @@ AC_CONFIG_FILES(Makefile, [{
 	    echo 'distclean-local::; @$(RM) GNUmakefile uncommon.mk'
 	fi
     } > confmk$$.tmp && mv -f confmk$$.tmp Makefile &&
+	grep '^ruby:' Makefile > /dev/null ||
 	${MAKE-make} info-program | grep '^PROGRAM=ruby$' > /dev/null ||
 	echo 'ruby: $(PROGRAM);' >> Makefile],
 [EXEEXT='$EXEEXT' gnumake='$gnumake'])