Buserelin is a synthetic gonadotropin-releasing hormone (GnRH) analog which is more potent than natural GnRH. Prolonged administration of the drug produces, after a short phase of stimulation, a selective and durable inhibition of secretion of pituitary gonadotropins, resulting in medical castration. In pilot and controlled studies buserelin shows a response rate that is similar to that of diethylstilbestrol or orchiectomy in the palliative treatment of advanced prostatic cancer, but larger and better designed studies are needed before reaching definitive conclusions about the duration of response and survival. The most common adverse effects of buserelin are loss of libido and/or impotence, hot flushes and possible flare-up of prostatic carcinoma symptoms in the first week of therapy. The combination of buserelin with an antiandrogen could avoid the flare syndrome; whether the combination has advantages compared to administration of buserelin alone requires confirmation from the large randomized studies still in progress.