This study was undertaken to investigate the effects of the immunocastration on the growth performance, the characteristics of carcass and meat quality in boar. Total 45 piglets(Landrace×Yorkshire) were prepared from the birth and were fed the experimental diet by the time to be slaughtered at around 110 kg of body weight. The experimental groups consisted of five piglets per pen with 3 replicates in three treatment groups, non castrated(NC), surgically castrated(SC), and GnRH antagonist(GA). In SC group, all piglets aged 3-4 days after birth were castrated by the surgical method. For the immunocastration, 2ml of GnRH antagonist(Improvac, Pfizer, Australia) were subcutaneously injected into piglets twice on the 16th and 20th week after the beginning of the trial in the GA group. The immunocastration did not make any significant influences on the growth performance, as compared with the other treatments. The different castration method used in either GA or SC group pigs had similar effects on the dressing percentage and body fat content as carcass parameters. In respect of a meat quality, the meat color, pH, shearing force and cooking loss were not significantly different in all treatment groups. Testosterone concentration in serum was shown to be similar between GA and SC group at 2 weeks after the 2nd injection of GnRH antagonist. The weight of bulbourethral gland and the radius and weight of testis were significantly smaller in GA than in NC(P=0.002). All together, this study suggested that the castration by immunocastration can be an alternative method for the surgical castration without any changes in growth performance, the characteristics of carcass and meat quality shown in surgical castration group.