Forty-two women with symptomatic uterine myomas, candidates for myomectomy or hysterectomy, were randomized to 6 months' treatment with buserelin 1200 micrograms/day intranasally (n = 22) or immediate surgery (n = 20). After buserelin treatment or operation the patients were followed for at least 12 months. Buserelin was well tolerated, the uterine volume fell from 465 +/- 168 to 273 +/- 88 cm3, and hemoglobin values normalized in all anemic patients. Rapid myoma regrowth was observed in all patients in the buserelin group after treatment withdrawal. Pregnancy occurred during follow-up in one of five buserelin-treated myomectomy candidates. Menorrhagia recurred in eight of 15 buserelin-treated hysterectomy candidates, and a hysterectomy was required but no transfusion was needed. Two women entered natural menopause and were considered cured. In the surgery group all operations were uneventful: three women conceived after myomectomy, whereas four of the patients that underwent hysterectomy required transfusions. Thus buserelin treatment appears to be indicated for infertile patients when surgery is contra-indicated or could cause adhesions, and for hysterectomy candidates in perimenopausal age and/or with secondary anemia.