Endometrial carcinoma (EC) is the most common extracolonic tumor associated with hereditary nonpolyposis colorectal cancer (HNPCC). HNPCC increases the risk of EC compared to the general population. Patients with HNPCC have a better prognosis than patients with common sporadic colorectal cancer. It is unknown, however, whether the survival rate of HNPCC-associated EC is higher than that of sporadic EC. The aim of our study was to compare the survival rates of HNPCC-associated EC with sporadic EC. From the registry of the Netherlands Foundation for Hereditary Tumors, 50 patients with HNPCC-associated EC from 46 families harboring a germline mutation or fulfilling the Amsterdam Criteria II were age- and stage-matched with 100 patients with sporadic EC registered in the Eindhoven Cancer Registry in the Netherlands. Survival rates were analyzed. The overall 5-year cumulative survival rates for patients with HNPCC-associated EC was 88% and 82% for patients with sporadic EC (p = 0.59). In Stages IA, IB and IC, the survival rates of patients with HNPCC-associated EC and sporadic EC were 92% and 91%, respectively (p = 0.90). In Stages IIIA and IIIC, the survival rates for HNPCC-associated EC and sporadic EC were 72% and 50%, respectively (p = 0.38). Furthermore, there was no significant difference in the distribution of tumor histologic subtypes in the study and control groups (p = 0.55). The outcomes in survival in EC in the general population and in women from families with HNPCC do not differ significantly. These results may have important implications in our understanding of EC and the role of early screening. © 2002 Wiley-Liss, Inc.