Rubella HI antibody of 67 samples was detected with one-day chick red blood cell (R.B.C) which was stablized by the treatment of carbon monoxide gas and the fixation of formalin. These anibody tires were compared with the titres of goose R.B.C's method. The signficient correlation between the two methods was 85%. In addition, U-plate might be used as well as V-plate in one-day chick R.B.C's technique.