Background: All-trans retinoic acid (ATRA), an active metabolite of vitamin A, is widely used for induction of differentiation, growth and proliferation of epithelial cells. Anticancer drug cisplatin induces apoptosis by cross-linking to DNA that it is commonly used for treatment of ovarian, head and neck, esophageal, and gastric cancers and melanoma. Previous studies on ovarian cancer and melanoma cell lines, suggesting additive effects of retinoic acid with cisplatin. The present study is the first study on simultaneous effects of all-trans retinoic acid and cisplatin on human esophageal cancer cell line KYSE-30.Material and Methods: In this experimental study, KYSE-30 cell line was cultured in presence of different concentration of ATRA alone and in combination with cisplatin. Then, cell death was investigated by clonogenic assay and acridine orange/ ethidium bromide staining.Results: The results showed that ATRA concentrations ≥15mM cause differentiation of KYSE30 to squamous cell morphology, while lower concentrations decreases the colony formation (p≤0.05). The best effects on cell death were observed in 10 mM of ATRA of combination with 5 and 10 mg/ml of cisplatin.Conclusions: Concomitant use of low concentrations of retinoic acid and cisplatin increases apoptosis and necrosis, thus reducing the number of cell line KYSE-30 colonies compared with cisplatin alone.