The effect of several potential antioxidants were examined as a means of increasing the in vitro development of in vitro matured and in vitro fertilized oocytes into morulae and blastocysts. Korean native cattle embryos after in vitro fertilization were cultrued for 7 days at 38.5$^{circ}C$ in CR1aa containing varing concentration of the antioxidants in a gas phases consisting of 5% CO2, 95% humidified air. The results obtained were summarized as follows; The proportion of embryos developed to morulae and blastocysts in CR1aa containing 2.5uM $alpha$-tocopherol(11.0% and 6.0%) was significantly higher than those of 0, 5.0, and 7.5uM $alpha$-tocopherol (P<0.05). concentration of 50uM L-ascorbic acid (7.5% blastocysts) did affect the proportion of embryos developing into blastocystes(P>0.05). Addition of 200uM cysteamine was significantly higher than those of 0, 100 and 300uM (P<0.05). When the fertilized oocytes were cultured at 0. 200, 400 and 600uM of selenium for 168 hrs, the morulae rates were 12.2, 5.2, 16.0 and 16.1% respectively, and addition of 200uM selenium was significantly higher than those of 0, 400, 600uM (P<0.05). These results suggested that the addition of $alpha$-tocopherol, L-ascorbic acid, cysteamine and selenicum can enhanced development to the morulae and blastocysts of in vitro derived fertilized oocytes.