Introduction: DEHP [di(2-ethylhexyl) phthalate)] is widely used in plastic industry and some reproductive toxicity has been shown with it. So, this study was designed to evaluate DEHP effects on resumption of meiosis and in vitro maturation of mouse oocytes as well as development of embryos resulted from them. Material and Methods: Mice of 4-6 weeks old were administered daily doses of 50, 100, 200 µl of 2.56 µM DEHP solution for 12 days. Immature mouse oocytes were recovered from all experimental groups and matured in MEM-α medium containing 5% FCS with and without 7.5 IU hCG and 100 mIU rFSH. IVF was performed T6 medium. Results: Resumption of meiosis and in vitro maturation were significantly lower in all experimental groups in culture media without hormones compared to controls. Fertilization and embryo development were also significantly decreased in both culture media (with and without hormones). Conclusions: This study showed the adverse effects of DEHP on in vitro maturation and embryo development in a dose dependent manner.