This study was investigated to examine the effect of conditioned medium from bovine oviductal cell(BOEC) in the co-culture system with BOEC on in vitro development of in vitro produced bovine embryos. Oocyte-cumulus complexes were cultured for 24 hrs in TCM-199 supplemented with 10% fetal calf serum, 1$mu extrm{g}$/ml FSH and 21U hCG, 1$mu extrm{g}$/ml oestradiol-17$eta$ at 39$^{circ}C$ under 5% CO2 in air. In vitro fertilization was performed with epididymal sperm and heparin (10$mu extrm{g}$/ml, 15min.) or caffeine(2.5mM)-treated spermatozoa. Oocytes were incubated with 1$ imes$106 spermatozoa/ml for 18 hrs and then cultured in various culture system for 7 days. The development rates of 16-cell or blastocyst stages were recorded on 4, 7 days, respectively, after incubating. The proportions ofembryonic development into molulae and blastocysts were higher in cumulus cell co-culture(23.4%) and BOEC co-culture(34.3%) than in M199-FCS(6.1%). Similarily, the development rates into molulae and blastocysts were significantly higher in BOEC-conditioned medium than those in M199-FCS. Therefore, it is suggested that BOEC co-culture and BOEC conditioned medium increase significantly the development of in vitro produced bovine embryos in in vitro system.