This study was perfomed to investigate the differentiation of rabbit blastocysts microinjected with testosterone solution. A total of 140 mixed breed does was superovulated, synchronized and hand mated. The eggs were flushed from uterine horns between 65 and 89 hrs after mating. Testosterone was dissolved in 95% ethanol and diluted with PBS at the ratio of 1: 99. Final concentration of testosterone was adjusted to 1 pg /ml. 6~8 bias-tocysts were microinjected with 1~10 p Q of the diluted testosterone solution, and tranfer-red into the uterine horns of the synchronized recipients. When 140 donor does were treat-ed with a single does of 200 IU PMSG in combination with 100 IU RCG 48 hrs apart, 134 of them(97%) showed standing estrus. Ovarian responses of 117 does were examined following mating and the rate of ovulation was 11.23 i 1.20. Ova were recovered from donors between 65 and 89 hrs after mating. Recovery rates of ova were 37.5% and 42.2% of recovered ova were blastocysts. A total of 106 blastsocysts were microinjected with testosterone solution and transferred into the uterine horns of 15 synchronized recipient does. One of the recipients was pregnant and delivered 7 baby rabbits. The external genitalia of the young rabbits appered to be the same appearance as the buck entierly.