The present study was performed to investigate the effects of co-culture with granulosa cells on in vitro fertilization and cleavage of early bovine embryo development. Bovine oocytes were matured for 20-24 hrs in vitro with granulosa cells or without and then fertilized in vitro using frozen-thawed spermatozoa treated with BO-caffeine, BO-BSA(2OmM heparin added). At l8hrs after insemination, oocytes were fixed and examined or further cultured in TCM 199 for 48hrs. The fertilization rates between the control(70.4%) and the groups of co-cultured with granulosa cell(2.5$ imes$106 cells/ml; 71.6%, 5.0$ imes$ 106/ml; 71.9%, l.0$ imes$ 107/ml; 71.1%) did not differ significantly. The cleavage rates in the groups co-cultured with granulosa cell(2.5$ imes$ 106 cells/mi; 43.6%, 5.0$ imes$ 106/ml; 46.8%. l.0$ imes$ 107/ml; 45.0%)were significantly higher than that of without granulosa cell, respectively(P<0.05). However there were no significant differences between the groups co-cultured with granulosa cells. The result indicated that co-culture with granulosa cell was effective means to cleavage of bovine follicular oocytes but did not affect the in vitro fertilization.