Reduced or missing sperm production is the main reason for infertility in a third of the couples who seek treatment. An uncommon cause of testicular failure is hypogonadotrophic hypogonadism. This review article discusses causes of this condition in men, medical treatment and prognosis with regard to fertility.The review is based on a recent literature survey and many years of clinical experience with infertile patients.Hormonal regulation of the spermatogenesis involves complex interaction between structural elements (paracrine and endocrine) in the testicle and the endocrine system. Hormonal treatment of men with hypogonadotrophic hypogonadism comprises injections of gonadotrophins, administered by the patient in close cooperation with a specialist. It may be necessary to maintain this treatment for up to two years, but it is usually effective in initiating or restoring of spermatogenesis.