This study emphasizes the protective effect of melatonin against the aluminum accumulation in some organs of rats. Twenty eight male Wistar rats were divided into four groups (n=7 animals for each), one control and three experimental, and aluminum sulphate and melatonin were applied in drinking water for three months as follows: group I: aluminum sulphate (1000 ppb in water), group II: aluminum sulphate (1000 ppb in water) and melatonin (10 mg in 100 mL water) and group III: melatonin (10 mg in100 mL water). Control group: water. Aluminum was accumulated in liver, kidney, heart, spleen and brain of exposed rats in significantly higher amounts compared to the control group. The findings showed that melatonin administration reduced the aluminum level in studied organs and melatonin had a protective effect against aluminum accumulation.