The study assessed p53 and p16 immunoexpression in 20 cases of ovarian serous carcinomas and four cases of serous borderline tumors, the results being statistically analyzed in relation to clinicopathological data of the cases. The p53 immunoreaction was observed in 85% of cases, the medium percentage of positivity being 15% for borderline tumors, 45% for low-grade carcinomas and 60% for high-grade carcinomas. The p16 immunoreaction was observed in 75% of cases, the medium percentage of positivity being 30% for borderline tumors, 25% for low-grade carcinomas and 62% for high-grade carcinomas. The p53 and p16 reaction was also identified at the tubal epithelium in cases of invasive carcinomas. Statistical analysis indicated significant differences in p53 expression depending on tumor type and for p53 and p16 expression compared to the degree of tumor differentiation. The study indicated a diffuse immunostain for p53 and p16 in high-grade serous ovarian carcinomas. The presence of "p53 signature" and areas with variable tumor differentiation and reactivity, in the case of high-grade carcinomas, supporting the existence of multiple mechanisms of their occurrence and progression.