These studies were conducted to investigate the microbe control effect of antibiotics treatment in all media used for in vitro fertilization(IVF) embryo production. The bovine oocytes were recovered from follicles(2~5mm) and were cultrued for 22hrs at 38.5$^{circ}C$ with 5% CO2 incubator. The contamination and development rate in vitro fertilized oocyte was evaluated everyday. The results were summerized as follow ; 1. Control, antibiotic-antimycotic solution(AAS, Gibco) 1%＋gentamycin, and AAS 1%＋kanamycin(Sigma, USA) treatment was contaminated with 72hrs. However Baytril and Kanamycin(Korea) added was not contaminated. 2. The blastocyst formation rate in Baytril supplementated 1, 2 and 3${mu}ell$/ml was 3.73, 1.28 and 0.00%, respectively. 3. The blastocyst formation in kanamycin added concentration of 50, 75 and 100$mu extrm{g}$/ml was 13.0, 9.4 and 3.49%, respectively.