Lower pregnancy rates of in vitro matured oocytes compared to those of in vivo stimulated cycles indicate that optimization of in vitro maturation (IVM) remains a challenge. Reduced developmental competence of in vitro matured oocytes shows that current culture systems for oocyte maturation do not adequately support nuclear and/or cytoplasmic maturation. Therefore this study evaluates the effects of different concentrations of saffron (Crocus sativus L.) aqueous extract (SAE), as an antioxidant agent on IVM of immature mouse oocytes. In this experimental study ,cumulus-oocyte complexes (COCs) were collected from 6-8 weeks old novel medical research institute (NMRI) female mice at 37°C. The rates of maturation, fertilization and development were recorded. ANOVA and Duncan’s protected least significant test, using the SAS program was applied for all statistical analysis. The maturation rate was significantly higher in all groups treated with different fertilization rate of oocytes and in vitro developmental competence when compared with The results of this study indicate that lower concentrations of SAE are more appropriate to be added to maturation medium when compared with other experimental and control groups. Generally, we conclude that addition of appropriate amounts of natural extracts such as SAE to maturation medium improves oocyte maturation and embryo development.