This study was carried out to investigate the effects of extenders such as Beltsville thawing solution(BTS), Modena and Androhep, preservation temperature and period of liquid boar semen on semen characteristics and reproductive performance. Boars were raised at Swine Artificial Insemination Center in National Livestock Research Institute, Sunghwan, Chungnam, Korea. This experiment was carried out from 1995 to 2000. The results obtained were summarized as follows. 1. Sperm motility in the samples with Androhep and BTS reduced from day 5 and in the samples with Modena reduced from day 3 of storage. pH or 3 extenders varied from 6.24 to 7.04 during day 1 to 5 of storage. Farrowing rate of sows inseminated with liquid boar semen offended with BTs, Modena and Androhep extenders did not show any differences until day f after semen collection. Sows inseminated with Androhep extender had better farrowing rates (P＜0.05) than those with Modena extender at day 1 or 5 after semen collection, but farrowing rates after AI using BTS did not differ compared to those Androhep and Modena. Litter size did not show any differences among the three extenders, but Androhep had the decreased litter size from day i of storage. 2. Motility and normal acrosome of the sperm preserved at 5$^{circ}C$ did not show any differences until day 4 of storage, but those at 17$^{circ}C$ changed from day 3 and 4, respectively. Farrowing rate of sows artificially inseminated with liquid boa. semen preserved at 17$^{circ}C$ had higher, than at 5$^{circ}C$ (p＜0.05), but there was no significant differences in litter size. Farrowing rates and litter size were decreased from day 2 and day 3 of storage at 17$^{circ}C$, respectively. Farrowing rate of sows inseminated with the preserved semen at 5$^{circ}C$ did not changed until day 4, but the litter size at 5$^{circ}C$ was lower than that at 17$^{circ}C$.