Abstract Background Ovarian cancer is the leading cause of gynecological cancer-related mortality. The novel oncogene S100A10 has been reported to be involved in cancer cell proliferation, invasion and metastasis. The role of S100A10 in ovarian cancer has not been well studied and the effect of S100A10 on chemotherapy remains unclear. The aims of the present study were to investigate the functional role of S100A10 in the progression and carboplatin sensitivity of ovarian cancer. Methods We examined the expression levels in tissues of S100A10 in 138 cases of ovarian cancer by IHC. To determine the functional roles of downregulated S100A10 in ovarian cancer, cell proliferation, colony formation, cell migration and invasion assays were performed. Chemoresistance was analyzed by apoptosis assay. A xenograft tumor model was established to confirm the role of S100A10 in carboplatin resistance in vivo. Using Western blot assays, we also explored the possible mechanisms of S100A10 in ovarian cancer. Results The results showed that increased expression of S100A10 was positively associated with carboplatin resistance (P