Abstract: Objective: To explore the effects of melatonin combined with cisplatin on the proliferation and apoptosis of Eca109 cells. Methods: Eca109 cells were co-cultured with different concentrations of melatonin combined with or without cisplatin 2. 5 mg /L. The inhibiting effects on the proliferation of Eca109 Cell were examined using MTT assay,and the inhibitory rate was analyzed. The cloning cell colony formation was observed using colony clone forming experiment,and the cell apoptosis rate was detected using flow cytometry after treatment. Results: The inhibitory rates of Eca109 cells induced with different concentrations of melatonin combined with cisplatin 2. 5 mg / L were significantly higher than that in Eca109 cells induced with cisplatin or melatonin alone( P 0. 01). Melatonin combined with cisplatin could obviously enhanced the inhibitory effects on colony formation of Eca109 cells. The apoptosis rate of Eca109 cells induced with 10-5mol / L of Melatonin for 24 h was 7. 8%. The apoptosis rate of Eca109 cells induced with 10-5mol / L of Melatonin combined with 2. 5 mg / L of cisplatin for 24 h was 32. 0%,which was higher than that in cells induced with only cisplatin( 9. 7%)( P 0. 01). Conclusions: Melatonin can enhance the anti-proliferative and apoptosis-inducing effects of cisplatin on Eca109 cells, which provide the basis of clinical treatment for esophageal cancer.