We have studied the endocrinological pattern in a girl with McCune-Albright syndrome. The young patient showed: normal prepubertal serum levels of gonadotropins, fluctuating estrogen concentrations, which sometimes were similar to the levels in adult women of fertile age, hyperprolactinemia with galactorrhea, ovarian cysts. The effects of treatment with antiandrogen drug, cyproterone acetate, and of a LHRH agonist, buserelin (less than D-Ser[TBU(8)6-des-gly NH2.10 greater than LHRH ethylamide), were studied. Cyproterone acetate with or without buserelin did not fully suppress estradiol concentrations. On the other hand, surgical resection of these cysts resulted in both clinical and endocrinological remission. It is likely that in this case of McCune-Albright syndrome precocious puberty was a result of ovarian estrogen secretion, while pubertal activation of the hypothalamus-pituitary axis was absent. Hyperprolactinemia, which appeared after the beginning of the combined therapy with buserelin and cyproterone acetate, was probably due to the elevated estrogen levels.