Multifactorial regulation of testicular endocrine and exocrine functions depends on gonadotropin control and cross-talk between different types of cells. Evidence is accumulating that cell-cell interactions between Leydig, Sertoli and peritubular myoid cells involved in male reproductive function may implicate several factors such as cytokines which play an important role in untercellular communication and exert broad pleiomorphic activities. In reproductive pathophysiology, the role of certain cytokines has been under intense scrutiny since their expression and production by the different parts of the male genital tract appear to be at least partially hormone-dependent Cytokines also modulate hormone activity. In vitro, they modulate steroidogenesis and affect spermatogenesis and sperm functions. Human seminal plasma contains several cytokines (tumor necrosis factor alpha, interleukin, transforming growth factor...) and their soluble receptors. A better understanding of these mediators in semen of normal men and patients with andrological diseases will contribute to a new approach to the management of male fertility.