We hypothesize that adiponectin and leptin may be capable of mediating some of the effects that body weight has on prostate cancer and that a mouse model may be effective to examine this hypothesis. We found that tumors from the TRAMP prostate cancer model expressed adiponectin and leptin receptors. TRAMP-C2 prostate cancer cell proliferation was reduced by adiponectin. Leptin was able to block the ability of adiponectin to reduce cell proliferation through altered signaling of the ERK pathway. Overall, this work suggests that adiponectin, leptin, and their receptors may play an important role in prostate cancer.