This study was conducted to investigate the immunohistochemical localization of ghrelin and IGF-I in the liver and kidney tissues in melatonin-treated rats. Rats were divided into three groups as a control, a sham and a treatment groups. While the treatment group received melatonin (10 mg/kg i.p.) for 3 weeks, only ethanol and saline solution were administered to the sham group. The control group received nothing.