diff --git a/ChangeLog b/ChangeLog
index ea83cb89c8..fb7d6ab70b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Thu Jun 19 17:19:14 2008  Yukihiro Matsumoto  <matz@ruby-lang.org>
+
+	* string.c (rb_str_scan): String#scan should preserve last
+	  successful match data.  [ruby-dev:35106]
+
 Thu Jun 19 16:49:36 2008  NAKAMURA Usaku  <usa@ruby-lang.org>
 
 	* missing/acosh.c (atanh): should set ERANGE to errno if parameter
diff --git a/string.c b/string.c
index d123207fd4..3949a6e33a 100644
--- a/string.c
+++ b/string.c
@@ -5689,7 +5689,7 @@ rb_str_scan(VALUE str, VALUE pat)
 {
     VALUE result;
     long start = 0;
-    VALUE match = Qnil;
+    long last = -1, prev = 0;
     char *p = RSTRING_PTR(str); long len = RSTRING_LEN(str);
 
     pat = get_pat(pat, 1);
@@ -5697,18 +5697,21 @@ rb_str_scan(VALUE str, VALUE pat)
 	VALUE ary = rb_ary_new();
 
 	while (!NIL_P(result = scan_once(str, pat, &start))) {
-	    match = rb_backref_get();
+	    last = prev;
+	    prev = start;
 	    rb_ary_push(ary, result);
 	}
-	rb_backref_set(match);
+	if (last >= 0) rb_reg_search(pat, str, last, 0);
 	return ary;
     }
 
     while (!NIL_P(result = scan_once(str, pat, &start))) {
+	last = prev;
+	prev = start;
 	rb_yield(result);
 	str_mod_check(str, p, len);
     }
-    rb_backref_set(match);
+    if (last >= 0) rb_reg_search(pat, str, last, 0);
     return str;
 }