This stduy was carried out to investigate the effect of concentration of PC12 and washing of sperm of sperm motility and acrosome reaction, and the effect of sperm incubated in mTALP solution containing PC12 112.5$mu extrm{g}$/ml on development of follicular oocytes matured in vitro. The results obtained were as follows. 1. When fresh sperm was once washed and then incubated in mTALP solution containing 0, 75, 112.5 and 225$mu extrm{g}$/ml PC12 for 15minutes, 225$mu extrm{g}$/ml showed significantly higher percent of acrosome reacted sperm than 0, 75, 112.5 and 225$mu extrm{g}$/ml. 2. When once or twice washed fresh sperm was cultured in mTALP containing 112.5$mu extrm{g}$/ml PC12 for 15minutes, no-washing showed significantly higher percent of motile sperm than that once- and twice-washing showed significantly higher percent of acrosome reacted seprm than no- and once-washing. 3. When sperm was cultrued in mTALP containing PC12, 112.5$mu extrm{g}$/ml for 15minutes and then was cocultured with bovine follicular oocytes matured in vitro, 11.2 to 22.4% of the oocytes were coleaved to more than 2cell stage.