This paper analyzes 18 endometrial carcinomas with different degrees of differentiation, the objective being to estimate involvement of p53 oncoprotein in the mechanism of endometrial carcinogenesis and the possible correlations with the tumoral proliferative activity evaluated by PCNA. The p53 immunoexpression was positive in 44.4% of the studied endometrial carcinomas, divided in three groups, the intensity of the immunostaining for p53 being increased for the low differentiated and undifferentiated endometrial carcinomas, whereas the differentiated endometrial carcinomas were moderate or low p53 positive. All the investigated tumors were PCNA positive, the PCNA index being of 40% in well-differentiated carcinomas, while in low differentiated and undifferentiated endometrial carcinomas the medium values of PCNA were of 60%, respectively 85%. Correlating the p53 and PCNA findings, we noted that PCNA was expressed especially in the cases with increased proliferative activity, without a significant statistic correlation between p53 and PCNA expression.