A prospective, routine histologic assessment of the omentum during primary surgery was conducted on 84 women with stage I endometrial carcinoma between February 1986 and June 1989. The purpose of the study was to determine the true incidence of omental involvement in early endometrial cancer and to detect risk variables associated with such metastases. Omental metastases were found in 7 (8.3%) of 84 patients with stage I endometrial carcinoma. A majority of the metastases (five) consisted of microscopic disease. Factors statistically significantly associated with omental metastasis were adnexal spread, cul-de-sac implantation, papillary serous carcinoma, a positive retroperitoneal lymph node and grade 3 tumor. The study indicated that silent metastases to the omentum frequently are neglected clinically in patients with stage I endometrial carcinoma during primary surgery and that a routine omental biopsy should be part of the procedure. Furthermore, for patients with high-risk variables, a complete omentectomy ought to be considered.