diff --git a/ChangeLog b/ChangeLog
index 157fa41873..5282b620af 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Mon Oct 27 15:55:04 2008  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* io.c (argf_init): initial value of $. should be 0.
+	  see [ruby-dev:36937].
+
 Mon Oct 27 15:38:38 2008  Yuki Sonoda (Yugui)  <yugui@yugui.jp>
 
 	* test/minitest/test_mini_test.rb
diff --git a/io.c b/io.c
index ff1c74a3e3..6e76f23c8b 100644
--- a/io.c
+++ b/io.c
@@ -5821,7 +5821,7 @@ argf_init(struct argf *p, VALUE v)
 {
     p->filename = Qnil;
     p->current_file = Qnil;
-    p->lineno = Qnil;
+    p->lineno = INT2FIX(0);
     p->argv = v;
 }
 
diff --git a/test/ruby/test_io.rb b/test/ruby/test_io.rb
index 4d9bb51fe3..4305293a3d 100644
--- a/test/ruby/test_io.rb
+++ b/test/ruby/test_io.rb
@@ -812,7 +812,7 @@ class TestIO < Test::Unit::TestCase
         f.gets; p $.
       end
     SRC
-      assert_equal("nil,1,2,2,1001,1001,1001,1,2,3,3", f.read.chomp.gsub("\n", ","))
+      assert_equal("0,1,2,2,1001,1001,1001,1,2,3,3", f.read.chomp.gsub("\n", ","))
     end
 
     pipe(proc do |w|