Introduction: Aluminum phosphide (ALP) poisoning is one of the deadliest types of poisoning in the world. The antioxidant properties of melatonin and N-acetylcysteine and their effects on reducing cell death have been identified. The aim of this study was to evaluate the effects of N-acetylcysteine and melatonin in the treatment of aluminum phosphide poisoning in rats. Materials and Methods: Fifty male Wistar rats weighing 200–250 g were tested in five groups of ten. The first group was the control group; the second group received (10 mg/kg) of ALP, the third group received (10 mg/kg) of ALP and (10 mg/kg) of melatonin, the fourth group received (10 mg/kg) of ALP and (10 mg/kg) of N-acetylcysteine, and the last group received (10 mg/kg) of ALP and (10 mg/kg) of melatonin and N-acetylcysteine. The plasma of samples was isolated, and the activity of antioxidant enzymes (glutathione S-transferase (GST), Superoxide dismutase (SOD), and catalase (CAT)) was analyzed. Results: The concentrations of CAT, GST, Glutathione, GSH were decreased in plasma, liver, and kidneys of mice treated with aluminum phosphide; also, the concentrations of aspartate aminotransferase (AST), ALT, and AlK were increased ( P < 0.05), while the activity of SOD did not change significantly ( P > 0.05). Treatment with N-acetylcysteine and melatonin led to an increase in the activity of CAT, GST, and GSH in plasma, liver, and kidney. After the administration of N-acetylcysteine and melatonin to mice, the levels of all enzymes were close to normal, and the mice survived for 12–15 hours after administration. Discussion: The administration of N-acetylcysteine (NAC) and melatonin at a dose of 10 mg/kg improves hepatic manifestations and prevents liver necrosis; also, they are considered potential therapeutic agents in the treatment of this poisoning.