Estrogen and progesterone receptors (ER, PR) were measured in leiomyomas and normal uterine tissues. Estrogen receptors concentration was higher in endometrium than in leiomyomas, lowest in normal myometrium. In the case of progesterone receptors, the concentrations in endometrium and leiomyomas were similar whereas that of myometrium was lower. ER and PR concentration were similar in leiomyomas of the uterine fundus, body and isthmus and steroid receptor content in the inner parts of large myomas was the same as in the outer parts. ER and PR concentrations in tumor-bearing myometrium were not different from those in myometrium of a control group.