Environmental estrogens (endocrine disruptive chemicals) have been shown to affect reproduction in wild life and it has been reported that maternal exposure with those chemicals have adverse effects on the male reproductive tract. However, little is known about the potential effects of prepubertal or pubertal exposure with environmental estrogens on the male reproductive tract. Here we examine plasma hormone levels and histology in the testis of mice following either 4- or 8-week oral administration of bisphenol A. Plasma free testosterone levels were dramatically decreased following 8 weeks of bisphenol A treatment compared with control group and morphologically multinucleated giant cells having greater than three nuclei were found in seminiferous tubules in the testis following the 8-week bisphenol A treatment. No differences in plasma corticosterone and luteinizing hormone levels were seen between bisphenol A and control groups. Thus, exposure with bisphenol A around pubertal period may directly disrupt the male reproductive tract. These facts suggest that more detailed studies will warrant the assessment of the risk to the developing human testis from exposure to bisphenol A and other environmental estrogens in prepubertal and pubertal period.