Abstract: The cytoplasmic maturation of oocytes was evaluated according to the monolayer distribution of cortical granule (CG) beneath the plasmalemma following fluorescent staining. Effects of epidermal growth factor (EGF) and insulin growth factor-1 (IGF-1) on the cytoplasmic maturation of buffalo oocytes were examined in this study. Results showed that all EGF at the concentration tested (10, 20, 30, 50 ng/mL) could promote the maturity of buffalo oocyte cytoplasm, the distribution pattern of CG changed gradually from middle to cortex with the concentration of EGF increased. The maturity of buffalo oocyte cytoplasm was also improved significantly by adding 30 ng/mL IGF into the maturation medium (P<0.05), the distribution pattern of CG changed gradually from middle to cortex as the concentration of IGF-1 increased to 30 ng/mL, and then changed gradually from cortex to middle as the concentration of IGF-1 increased to either 50 ng/mL or 100 ng/mL. More oocytes matured significantly when they were cultured in the maturation medium containing 20 ng/mL EGF and 30 ng/mL IGF-1 in comparison with them cultured in either 30 ng/mL IGF-1 or 20 ng/mL EGF groups(P<0.05). These results indicate that EGF and IGF-1 have a cooperative effects on the in vitro maturation of buffalo oocytes.