Between February 1, 1965, and December 31, 1985, 426 patients affected with Stage I adenocarcinoma of the endometrium were submitted to surgery in the Department of Gynecologic Oncology of the Regina Elena Cancer Institute. The value of the present survey is represented by the homogeneous diagnostic data on the basis of which the treatment was planned. Criteria of histological grading and myometrial invasion were always followed, making it possible to carry out a protocol combining surgery with radio-therapy, chemotherapy, and/or hormone therapy. In fact, an accurate evaluation of the grading, the infiltration of the myometrium, and the localization and size of the lesion are necessary to establish the risk of lymph node invasion. This last parameter is the most important as far as the therapeutic protocol, recurrences, and/or metastases and survival are concerned. The high 5-year survival rate, despite the high average age of the patients (74.7% between the ages of 51 and 70), associated pathologies, and the relatively low incidence of complications from treatment, demonstrate the validity of the protocol adopted.