This chapter focuses on the hormonal treatment of male infertility. Approximately 10% of all couples will seek fertility assessment. Male factors account for subfertility in 20 ± 25%. Even when a male factor is identified; a specific etiological diagnosis is not often established, leaving a large undiagnosed heterogeneous group of men with idiopathic oligo/asthenospermia. Clinical pregnancy rates of up to 33% have been consistently reported in large series studies. This chapter covers the physiology and etiology of male infertility, specific hormonal therapies, empirical hormonal therapies, gonadotropin-releasing hormone treatment, androgen treatment, estrogen blockade, dopamine agonist treatment, growth hormone treatment, empirical hormonal therapies in specific situations, hormonal cytoprotection for cytotoxic damage, and cryptorchidism. Empirical hormonal therapy of idiopathic male infertility has so far been universally disappointing, in contrast to the proven efficacy of gonadotropin replacement therapy.