SummaryThe male partner is the cause of childlessness in about one out of two barren couples. He may be completely infertile; however in most eases subfertility is found.Subfertility is the result of either intrinsic testicular deficiency in spermatogenesis, or general (endocrine) disease. Frequently it is due to disturbance in scrotal venous circulation or to“Section of the accessory sex glands.Chronic aspecific epididymitis is often difficult to detect on clinical or biochemical grounds and diagnostic (surgical) scrotal exploration may be indicated. The diagnosis of non-specific chronic Prostato-vesiculitis may be difficult as well, therefore the author develops a set of diagnostic criteria based on:1. Data from the patients history and clinical examination;2. Cytological and bacteriological analysis of the Prostatic expression fluid or urinary sediment alter prostatic massage.3. Cytological, biochemical and bacteriological examination of the ejaculate.The treatment of infectious or inflammatory disease of the accessory sex glands makes use of n appropriate antibiotic together with an anti-inflammatory drug. The treatment should be c°ntinued for a sufficiently long period of time.Varicocele is a frequent finding in subfertilemen. In 3/4 of cases the diagnosis is made by scrotal palpation; in 1/4 of cases however spermatic venous reflux may exist without clearly palpable varicosity of the scrotal pampiniform plexus.In these cases of subclinical varicocele, the diagnosis is based on scrotal telethermography and on retrograde venography of the internal spermatic vein.Since extra testicular factors in male subfertility may be treated succesfully, it is of the utmost importance to always perform systematic diagnostic work-up in order to detect this pathology.