The objectives of the study were to determine whether a low dose of a luteinizing hormone-releasing hormone analogue (buserelin) has an effect on testicular descent, if buserelin affects germ cell maturation and epididymal development, the incidence of retractile testes in the controlled trials, and if the subsequent administration of human chorionic gonadotropin has any effect on the groups treated. The study was double blind, placebo controlled in which patients with cryptorchidism were assigned randomly into 3 groups: buserelin treatment (22), surgical treatment (18) or placebo control group (19). The 3 groups of patients were similar before treatment in regard to testicular position, chronological and bone age, height and weight, luteinizing hormone, follicle-stimulating hormone, testosterone, penile size and the volume of the contralateral testis. Buserelin (20 micrograms). administered daily in a nasal spray significantly induced testicular descent compared to the group treated with a placebo (p less than 0.01). A normal epididymis was found more often in boys with successful descent (p less than 0.003). Boys treated with buserelin had the highest number and the best maturation index of the germ cells; human chorionic gonadotropin influenced the descent in both groups but it was more efficacious when it was administered after treatment with buserelin, although it had no additional effect on germ cell maturation. None of the boys had retractile testes. Buserelin was capable of inducing testicular descent in addition to increasing simultaneously the number of germ cells and provoking further development of the epididymis.