Simultaneous carcinomas involving both the ovary and the endometrium may cause diagnostic difficulties, particularly if the tumors have a similar histology. We report two cases of independent endometrioid carcinomas of the endometrium and the ovary. Tumor development was synchronous in one case and metachronous in the other. These cases illustrate the morphological criteria helpful in distinguishing independent primaries from metastatic carcinomas which have a different therapeutic implication. Endometrial tumors were intra-mucosal without myometrial or vascular invasion, or tubal involvement and were associated with atypical complex hyperplasia (case 2). The ovarian tumors were uninodular, unilateral, without hilar invasion and were associated with endometriosis (case 2). The prognosis of endometrioid type carcinomas is better than for other histological types of carcinoma. Both our patients are well and disease free at 27 and 24 months.