Objective To investigate the effects of ofloxacin on mouse embryonic development and to determine wether ofloxacin is of reproductive and teratogenic toxicity. Methods\ Ofloxacin was administered orally by gavage to groups of inseminated mice for 3 days (day 0 to day 2 post insemination) and for 10 days (day 0 to day 9 post insemination), and to male mice for 10 days at a daily dose of 0, 36, 72 and 360 mg/kg b.w. respectively. The mouse fetuses were taken for examination at 16d of pregnancy. Results\ The results indicated that ofloxacin did not show effects on the number of living fetuses, dead fetuses and absorbed fetuses. The body weight, placenta weight of fetuses in all treatment groups had no significant difference (p>0 05) as compared with those of the control. Ofloxacin did not produce significant difference on the development of pre implantation embryos in female mice, but significant difference was observed in male mice. Conclusion\ The results of this study showed no evidence for reproductive and teratogenic toxicity of ofloxacin.