The membrane cofactor protein CD46 represents a complement inhibitor, which protects autologous cells from complement - mediated cytotoxicity. CD46 may exhibit the potential to protect tumor cells from the immune responses of the host. The present study aimed to evaluate the prognostic significance of CD46 expression in ovarian cancers. The analyses were performed on 73 ovarian cancer samples. Immunohistochemical reactions were performed on paraffin sections of tumors using monoclonal antibodies directed against CD46. The immunohistochemical reactions and the clinical observations results were subjected to statistical analysis. Expression of CD46 was demonstrated in 60% of primary laparotomy cases and in 70% secondary cytoreduction cases. Kaplan-Meier analysis showed that a significantly shorter revival-free time was linked to cases with CD46 expression at PL (p=0.01). Ovarian cancers manifest CD46 expression that is linked to a less favourable prognosis.