Some human endometrial carcinomas contain receptors for estrogen (E2) and dihydrotestosterone (DHT). Analysis of 50 primary endometrial carcinomas by agar gel electrophoresis revealed a varying receptor pattern, absence of both receptors, sole presence of E2- or DHT- receptor, or presence of both. Highly differentiated tumours often had receptors of both types (7/18) and poorly differentiated tumours most often lacked them (1/10). Primary tumours with metastases (Stages III-IV) seldom had combined receptors, only in 2 cases out of 9. Growth of the tumour down in the cervical canal (Stage II) implied absence of combined receptors in all of the 13 cases studied. In 8 different ovarian tumours, presence of either E2- or DHT-receptors was found in 6. The findings are discussed in relation to hormonal treatment of the disease.