Young's syndrome is characterized by azoospermia due to bilateral epididymal obstruction associated with chronic sinobronchial disease. We report two Japanese cases of Young's syndrome who were treated with microsurgical epididymovasostomy. The histopathology of the caput epididymis showed an obstruction at the most distal region of the ductuli efferentes. The incidence of Young's syndrome in patients with obstructive azoospermia was much lower for mongoloids than for Caucasians.