Objective : To ascertain if hydrosalpinges are associated with reduced pregnancy rates and increased pregnancy loss after IVF-ET, a study was conducted. Increased volume and leakage of hydrosalpinx fluid may exert negative effects on follicular development and embryo quality and/or render the uterine environment hostile to embryogenesis. This study was undertaken to examine the effect of hydrosalpinx fluid an mouse embryogenesis in vitro. Methods :The study was designed by comparison of mouse embryo blastulation rate in media containing increasing concentrations of hydrosalpinx fluid. In vitro fertilization rate and the development of one-, two-, four-cell mouse embryos in medium containing 0% (Control), 0.3%, 0.6%, 0.9%, 5%, 10% and 20% of human hydrosalpinx fluid-containing media was observed. Results :In vitro fertilization and culture of mouse embryo at 0% (control), 0.3%, 0.6%, 0.9%, 5%, 10%, 20% hydrosalpinx fluid concentrations demonstrated significantly 1ower blastulation rate at each level compared with the controls (p<0.05). In vivo fertilization and culture of embryo at the same increasing concentration of hydrosalinx fluid showed the same results (p<0.05). And the difference of each embryo development (zygote, 2cell, 4cell) was not significant. Conclusion :Hydrosalpinx fluid is highly embryotoxic. Procedures such as, salpingectomy ar proximal tubal occlusion to circumvent the passage of hydrosalpinx fluid into the uterine cavity may have beneficial effects on the developmental environment for embryos in vivo.