Objective: To explore the effects of CD146 overexpression in ovarian cancer cell line SKOV3 on the tumorigenesis in nude mice. Methods: The lipofection-mediated transfection in SKOV3 cells was performed and transfectants were screened by G418 resis- tance to obtain positive clone cells that overexpressed CD146 protein confirmed by Western blot. MTT assay and colony formation assay on soft agar were used to evaluate the proliferation and colony formation ability of SKOV3 cells that overexpressed CD146, respectively. These positive cells were subcutaneously injected into the nude mice, and the tumorigenesis of SKOV3 was observed and recorded every week until the sacrifice of the nude mice. The tumor weight and volume were measured and immunohistochemical staining was used to detect CD146 expression in the tumor tissue of nude mice. Results: After lipofection and G418 screening, the positive clone cells over- expressed CD146 were selected. CD146 overexpression significantly inhibited cell proliferation and decreased colony formation ability in SKOV3 cells in vitro, and also inhibited the tumorigenesis of SKOV3 in the nude mice. The tumor weight and volume from the nude mice injected subcutaneously with overexpressed-CD146 SKOV3 cells were respectively lighter and smaller than those of the control （P < 0.05). Immunohistochemical staining showed that tumor tissues from nude mice injected with overexpressed-CD146 SKOV3 cells still could express high level of CD146 protein. Conclusion: CD146 overexpression can inhibit cell proliferation in vitro and tumorigene- sis of SKOV3 in nude mice. CD146 may be a potential marker for ovarian cancer prognosis.