The paper describes a new and rapid method forregistration of spermatogenesis in human testes: the testicular biopsy score count. Each tubular section is given a score from 10 to 1 according to presence or absence of the main cell types arranged in the order of maturity. Presence of spermatozoa scores 10, 9 or 8; spermatids (and no further) 7 or 6; spermatocytes (and no further) 5 or 4; only spermatogonia 3, only Sertoli cells 2 and no cells 1. The theoretical background of the score count method is discussed and it is emphasized that tissue heterogeneity, being a main point in most conditions, is exposed and evaluated by the method. Normal values are given and results obtained in 335 cases including a great variety of forms of male hypogonadism are presented. Patognomonic score counts leading to immediate diagnosis at a glance are obtained in many instances. A high correlation between testicular biopsy score count and sperm count is found and it is concluded that by this method it has for the first time become possible in man to correlate endocrine conditions with the functional state of the testicular tissue.