Expression of miR-34c is significantly reduced in human endometrial cancer cells and miR-34c regulates multiple genes associated with cancer cell proliferation, apoptosis and invasiveness. Thus, miR-34c can theoretically become a target that enhances chemotherapy. Upregulation of miR-34c to enhance the chemotherapeutic effect of cisplatin (DDP) has not been studied in human endometrial cancer cells before. In an in vitro study, the human endometrial cancer cell line, Ishikawa, was treated with DDP and miR-34c mimics, alone or in combination. IC50 values were dramatically decreased in cells treated with miR-34c mimics when combined with DDP, to a greater extent than those treated with DDP alone. Furthermore, miR-34c mimics significantly enhanced apoptosis in Ishikawa cells by inhibiting IL-6R expression. Therefore, a combination of miR-34c mimics and DDP could be an effective therapeutic strategy for controlling Ishikawa cell proliferation.