Sertoliform endometrioid adenocarcinomas of the ovary are well recognized but, curiously, a sertoliform pattern has not previously been noted in endometrioid adenocarcinomas of the endometrium. An endometrial tumour is described which showed in some areas the typical appearances of an endometrioid adenocarcinoma and in others a pattern closely resembling that of a Sertoli cell tumour.