diff --git a/transcode.c b/transcode.c
index 92fd806597..386942689a 100644
--- a/transcode.c
+++ b/transcode.c
@@ -2699,7 +2699,9 @@ str_transcode0(int argc, VALUE *argv, VALUE *self, int ecflags, VALUE ecopts)
 		if (!NIL_P(ecopts)) {
 		    rep = rb_hash_aref(ecopts, sym_replace);
 		}
-		*self = rb_str_scrub(str, rep);
+		dest = rb_str_scrub(str, rep);
+		if (NIL_P(dest)) dest = str;
+		*self = dest;
 		return dencidx;
 	    }
             return NIL_P(arg2) ? -1 : dencidx;