This research was conducted to study the in vitro fertilization of mice oocyte and the environmental factors which affect it. The results indicated that the fertilization in the laboratory by using the culture medium RPMI-1640 at 37 °C and pH 7.4 gave the best results and the percentage of fertilization was 63.73 % and the lowest percentage for abnormal embryo WdS 27.58%, the use of other culture media like Medicult IVF, Earl's + TCM-199 and TCM-199 gave fertilization percentages 38.75, 42.42 and 61.45 % respectively, also the percentages of abnormal embryo were 32, 35.7 and 33.89 % respectively. The obtained data showed that at 37 °C and RPMI-1640 culture medium gave the best results under used experimental conditions. However, fertilization at temperatures of 36, 38 and 39 °C was 40.47, 41.26 and 32.60 % respectively, also the percentages of abnormal embryo for these temperature were 39.47, 34.61 and 43.33 % respectively. While the best pH range for fertilization was 7.4 at RPMI-1640 culture media, the percentage of normal and abnormal embryo was 63.73 and 27.58 % respectively, the other pH values 7.0, 7.7 and 8.1 showed that the fertilization rate was 50.0, 48.75 and zero respectively, and the percentage of abnormal embryo was 37.5, 38.46 and zero respectively. The comparison between the differences in content of superovulated and non superovulated mice ovaries of DNA, RNA and protein, indicated that the superovulated ovaries gave lower concentration of DNA, higher concentration of RNA and protein (0.16, 2.67 and 0.73 ug/mg of tissue respectively) as compared with the concentrations in non superovulated ovaries (2.01, 1.35 and 0.5 ug/mg of tissue respectively). The results of protein profile from the superovulated and non superovulated mice ovaries indicated that the low molecular weight proteins in non superovulated ovaries are more than in superovulated ovaries.