OBJECTIVE: To assess the immunohistochemical expression of p53 protein, a tumour suppressor gene of the oncogene c-erb-B2 and MIB-1 proliferation marker (Ki-67 antigen) in endometrial carcinoma. METHODS: We studied 29 cases of endometrial carcinoma in which the p53, c-erb-B2 and MIB-1/Ki-67 antigens were investigated by an immunohistochemical method. We evaluated the correlations among the immunohistochemical positivity and the grading, depth of myometrial invasion, stage of the neoplasia and follow-up. RESULTS: Both p53 and c-erb-B2 were positive in 16 out of 29 cases (55.2%), whereas MIB-1 was positive in 19 out of 29 cases (65.5%). All these three antigens showed a positive correlation with the grading, myometrial invasion and FIGO stage. Regarding follow-up, p53, c-erb-B2 and MIB-1 were, respectively, positive in 100%, 83.4% and 66.7% of neoplasias of patients who died of disease whereas they were positive in 40%, 40% and 60%, respectively, of tumours of patients with no evidence of disease. CONCLUSION: The overexpression of p53, c-erb-B2 and MIB-1 seem to indicate a more malignant tumour phenotype.