Abstract: Objective To study the effect of extremely low frequency electrom agnetic fields on Bax and Bcl-2 expression in the spermatogenic cells of rats.Methods Sixty adult female Wistar rats were divided into 0.1 m T,12.8 m T and control group.After electrom agnetic radiation for 2 and 12 weeks,HE staining and immunohistochemical methods were used to detected Bax and Bcl-2 expression with image analysis.Results After electrom agnetic exposure for 2 week,the gray scale values of Bax were 25.58±4.98 and 39.17±4.33 for low and high intensity groups and that of Bcl-2 were 68.12±3.64 and 39.62±4.35.The gray scale values of Bax were 40.12±2.45 and 62.32±5.90 for low and high intensity groups for 12 weeks exposure and that of Bcl-2 were 55.7±2.43 and 23.84±3.62.Conclusion With the increase of exposure intensity and time,the Bax and Bcl-2 exprseeion in sperm atogenic cells in rats were gradually decreased.