Occupational influences on male fertility and sexuality are reviewed. The potential risks of physical factors (trauma, temperature, radiation, microwaves), of chemical factors (metals, mineral oils, hormones [oral contraceptives and estrogen] pesticides and herbicides, neurotoxins, vinylchloride and analogs, carbon disulfide), of physiopathological factors (infectious diseases occupationally acquired, low-back syndrome) and of psychological factors (stress, alcoholism) are discussed. The methodological aspects in monitoring the fertility and sexuality of male workers are considered. Physicians, practicing occupational medicine, are cautioned to be aware of these potential risks regarding gonadal function. Occupational hygienic measures are the 1st step in preventing environmental pollution hazards.