The aim of this study was to examine the effects of two kinds of rat hepatoma cell-conditioned media (CM) on in vitro development of bovine embryos matured and fertilized in vitro under chemically defined conditions. Medium conditioned with Reuber H-35 or BRL 3A cells was prepared by a 24-h culture in the absence of both serum and bovine serum albumin (BSA). Two days after in vitro fertilization, bovine embryos were cultured in these conditioned media. After 2 days of culture in the control or in BRL CM, 15-18% of embryos were developed to the morula stage. Although a significant difference was not found, the developmental rate was increased to 22.4% when embryos were cultured in Reuber CM. Additionally, the percentage of degenerated embryos cultured with Reuber CM was significantly decreased (33.5%; p<0.01) compared to that of control embryos (49.4%). These results demonstrated the positive effects of serum- or BSA-free Reuber CM on the inhibition of early degeneration of bovine embryos matured and fertilized in vitro.