The aim of this study is to evaluate the usefulness of tumor markers in the follow-up of patients with endometrial cancer. The sera of 23 patients with elevated pretreatment CA125, CA15.3, and CA19.9 were collected at each follow-up visit and analyzed. Eleven patients had normal posttreatment levels and none of them developed recurrence. Twelve patients had one or more increased tumor markers, 7 (58.3%) of them developed recurrence. Among these seven patients, six had CA125 elevated by at least 10-fold and one had elevated CA19.9. The median lead time between elevation of tumor markers and clinical evidence of recurrence was 6 months. Hence posttreatment elevation of CA125 is a useful predictor for recurrence in patients with elevated pretreatment levels.