Bisphenol A and low-dose estradiol promote the development of precancerous lesions in the pancreas of adult Syrian hamsters. Recent studies have demonstrated that bisphenol A (BPA) exhibits estrogenic activity. We previously showed that BPA alone induced precancerous lesions in the pancreas of young Syrian hamsters; however, the age of the animals, the dose and route of administration, and the period during which the pancreata were analyzed were important factors for such induction. Because the role of endogenous estrogen fluctuates with age, we examined the carcinogenic effect of BPA in a model that has low concentrations of endogenous estrogen. Adult male Syrian hamsters were injected with a low dose of estradiol (20 ng) every other day for 10 days and then treated with 0.1% BPA (w/v) in their drinking water. In this study, we showed that BPA induced precancerous lesions in the pancreas of both sexes when we followed these animals for 14 months. BPA-treated female hamsters had a greater number of adenomatous papillary neoplasms (APNs), which may be related to the differences in the levels of endogenous estrogen, than those of age-matched male hamsters treated with BPA. In addition, BPA treatment was shown to lead to alterations in the morphology of the pancreas and to increase the infiltration of both macrophages and neutrophils. These data may support the potential use of BPA as a promoter for precancerous pancreatic lesions.