diff --git a/ChangeLog b/ChangeLog
index 112e8212c7..ea44ddb900 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+Wed Dec 12 12:11:42 2007  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* re.c (rb_reg_regsub): should copy encoding.
+
+	* string.c (rb_str_sub_bang, str_gsub): should check and copy encoding
+	  to be replaced.
+
 Tue Dec 11 23:04:17 2007  Yukihiro Matsumoto  <matz@ruby-lang.org>
 
 	* pack.c (pack_pack): RDoc update.  a patch from Gary Wright
diff --git a/re.c b/re.c
index 76c42c393f..ea6c644498 100644
--- a/re.c
+++ b/re.c
@@ -2796,6 +2796,7 @@ rb_reg_regsub(VALUE str, VALUE src, struct re_registers *regs, VALUE regexp)
         rb_str_buf_cat(val, p, e-p);
     }
     if (!val) return str;
+    rb_enc_copy(val, str);
 
     return val;
 }
diff --git a/string.c b/string.c
index 9408b98245..2dadbbb82e 100644
--- a/string.c
+++ b/string.c
@@ -2370,15 +2370,19 @@ rb_str_sub_bang(int argc, VALUE *argv, VALUE str)
 
 	if (iter) {
 	    char *p = RSTRING_PTR(str); long len = RSTRING_LEN(str);
+	    rb_encoding *enc;
 
 	    rb_match_busy(match);
 	    repl = rb_obj_as_string(rb_yield(rb_reg_nth_match(0, match)));
+	    enc = rb_enc_check(str, repl);
 	    str_mod_check(str, p, len);
 	    str_frozen_check(str);
 	    rb_backref_set(match);
+	    rb_enc_associate(str, enc);
 	}
 	else {
 	    repl = rb_reg_regsub(repl, str, regs, pat);
+	    rb_enc_copy(str, repl);
 	}
 	rb_str_modify(str);
 	if (OBJ_TAINTED(repl)) tainted = 1;
@@ -2490,17 +2494,22 @@ str_gsub(int argc, VALUE *argv, VALUE str, int bang)
 	match = rb_backref_get();
 	regs = RMATCH(match)->regs;
 	if (iter) {
+	    rb_encoding *enc;
+
 	    rb_match_busy(match);
 	    val = rb_obj_as_string(rb_yield(rb_reg_nth_match(0, match)));
+	    enc = rb_enc_check(str, val);
 	    str_mod_check(str, sp, slen);
 	    if (bang) str_frozen_check(str);
 	    if (val == dest) { 	/* paranoid chack [ruby-dev:24827] */
 		rb_raise(rb_eRuntimeError, "block should not cheat");
 	    }
 	    rb_backref_set(match);
+	    rb_enc_associate(str, enc);
 	}
 	else {
 	    val = rb_reg_regsub(repl, str, regs, pat);
+	    rb_enc_copy(str, val);
 	}
 	if (OBJ_TAINTED(val)) tainted = 1;
 	len = (bp - buf) + (beg - offset) + RSTRING_LEN(val) + 3;
diff --git a/version.h b/version.h
index d1de4cbee7..9168e76ea0 100644
--- a/version.h
+++ b/version.h
@@ -1,7 +1,7 @@
 #define RUBY_VERSION "1.9.0"
-#define RUBY_RELEASE_DATE "2007-12-11"
+#define RUBY_RELEASE_DATE "2007-12-12"
 #define RUBY_VERSION_CODE 190
-#define RUBY_RELEASE_CODE 20071211
+#define RUBY_RELEASE_CODE 20071212
 #define RUBY_PATCHLEVEL 0
 
 #define RUBY_VERSION_MAJOR 1
@@ -9,7 +9,7 @@
 #define RUBY_VERSION_TEENY 0
 #define RUBY_RELEASE_YEAR 2007
 #define RUBY_RELEASE_MONTH 12
-#define RUBY_RELEASE_DAY 11
+#define RUBY_RELEASE_DAY 12
 
 #ifdef RUBY_EXTERN
 RUBY_EXTERN const char ruby_version[];