The study group consisted of 26 women with endometrial adenocarcinoma belonging to 19 cancer families. Age at the onset of cancer, the stage and histologic differentiation of the tumor, initial symptoms, other malignancies, 5-year survival, and transmission of cancer to descendants were studied. The focus was on the importance of endometrial carcinoma in the tumor spectrum. The diagnosis of cancer family was delayed in 14 of the 19 families because endometrial carcinoma was not included in the primary diagnostic carcinoma. This delay may have been harmful to 16 family members who had carcinomas later in life. In ten of the 14 women with multiple malignancies, endometrial adenocarcinoma was the primary malignancy diagnosed, thus enabling the suspicion of a gene carrier and screening for subsequent malignancies. The authors concluded that endometrial carcinoma is a significant component of cancer family syndrome and should be included in the main criteria of Lynch syndrome II.