diff --git a/ChangeLog b/ChangeLog
index 00d5025f6c..3f1214f33d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Tue Sep 16 00:57:56 2008  Tanaka Akira  <akr@fsij.org>
+
+	* re.c (rb_reg_quote): use rb_enc_mbcput to generate ASCII
+	  incompatible characters properly.
+
 Tue Sep 16 00:51:59 2008  NARUSE, Yui  <naruse@ruby-lang.org>
 
 	* encoding.c (Encoding#base_encoding): removed. [ruby-dev:36270]
diff --git a/re.c b/re.c
index c0280f545a..b47ec108e6 100644
--- a/re.c
+++ b/re.c
@@ -2860,34 +2860,34 @@ rb_reg_quote(VALUE str)
 	  case '*': case '.': case '\\':
 	  case '?': case '+': case '^': case '$':
 	  case '#':
-	    *t++ = '\\';
+            t += rb_enc_mbcput('\\', t, enc);
 	    break;
 	  case ' ':
-	    *t++ = '\\';
-	    *t++ = ' ';
+            t += rb_enc_mbcput('\\', t, enc);
+            t += rb_enc_mbcput(' ', t, enc);
 	    continue;
 	  case '\t':
-	    *t++ = '\\';
-	    *t++ = 't';
+            t += rb_enc_mbcput('\\', t, enc);
+            t += rb_enc_mbcput('t', t, enc);
 	    continue;
 	  case '\n':
-	    *t++ = '\\';
-	    *t++ = 'n';
+            t += rb_enc_mbcput('\\', t, enc);
+            t += rb_enc_mbcput('n', t, enc);
 	    continue;
 	  case '\r':
-	    *t++ = '\\';
-	    *t++ = 'r';
+            t += rb_enc_mbcput('\\', t, enc);
+            t += rb_enc_mbcput('r', t, enc);
 	    continue;
 	  case '\f':
-	    *t++ = '\\';
-	    *t++ = 'f';
+            t += rb_enc_mbcput('\\', t, enc);
+            t += rb_enc_mbcput('f', t, enc);
 	    continue;
 	  case '\v':
-	    *t++ = '\\';
-	    *t++ = 'v';
+            t += rb_enc_mbcput('\\', t, enc);
+            t += rb_enc_mbcput('v', t, enc);
 	    continue;
 	}
-	*t++ = c;
+        t += rb_enc_mbcput(c, t, enc);
     }
     rb_str_resize(tmp, t - RSTRING_PTR(tmp));
     OBJ_INFECT(tmp, str);
diff --git a/test/ruby/enc/test_utf16.rb b/test/ruby/enc/test_utf16.rb
index a7c735f436..7f807476aa 100644
--- a/test/ruby/enc/test_utf16.rb
+++ b/test/ruby/enc/test_utf16.rb
@@ -355,4 +355,10 @@ EOT
     assert_equal("", sl.chop)
     assert_equal("", sb.chop)
   end
+
+  def test_regexp_escape
+    s = "\0*".force_encoding("UTF-16BE")
+    r = Regexp.new(Regexp.escape(s))
+    assert(r =~ s)
+  end
 end