We searched for p53 protein accumulation in 72 gastric carcinomas. Of the 38 cases of the diffuse type, only four were positive for p53. Of the 34 cases of intestinal type, 24 had p53 protein accumulation. This difference (p < 0.0001) between histological types was present regardless of whether the carcinoma was superficial or infiltrative. Normal epithelial cells and intestinal metaplasia were never positive. No correlation was found between p53 protein accumulation and tumor size, lymph node metastases, age or sex of the patients. Although tumor size, lymph node metastases, and infiltrative character all have prognostic value, p53, either alone or in association with these parameters, does not; p53 mutations seem to play a role in oncogenesis only in the intestinal type of gastric carcinomas; however, p53 protein accumulation has no prognostic value in gastric tumors.