Ovarian cancer is the fourth cause of death by cancer among women and the first mortality cause in gynecological neoplasia. Our goal was to evaluate p53 and Ki67 immunoexpression and also the correlations with tumor stage and type. The study included 45 primary ovarian malignant mucinous tumors, diagnosed in patients in the IV and VI decade. From the standpoint of histopathology, there were 28 cases of borderline mucinous tumors and 17 mucinous carcinomas, predominantly stage I of the disease. The immunostaining for Ki67 was positive in all the cases, the highest levels being recorded in mucinous carcinomas (22.2% medium index) compared to the borderline tumors (9.5% medium index). Opposed to Ki67, the immunoreaction for p53 was present in 37.7% of all the tumors, predominantly in mucinous carcinomas where the stain has high values (52.3% medium index) in contrast with borderline lesions (15.5% medium index). The study indicated significant differences in p53 and Ki67 immunostain in relation to the tumor stage and histological type, there being a direct correlation of the expression of both proteins, in the studied tumors. P53 and Ki67 are useful markers for evaluating aggressive tumoral behavior and differentiating between mucinous carcinomas and borderline mucinous tumors.