Infections of the male accessory glands are potentially correctable causes of male infertility. But sexually transmitted pathogens generally have not been considered to be an important environmental determinant of male infertility except for obstruction of the epididymis or vas deferens. Despite the recent reports of several micro-organisms such as Chlamydia trachomatis and Mycoplasmataceae, evidences are still lacking to confirm the negative influence of sexually transmitted diseases on sperm quality. To establish the effect of sexually transmitted disease on male infertility, further studies with control group based on exact diagnostic criteria are requested.