One cause of secondary oligomenorrhea is ovarian infection. A rare type of infection related to the disturbance of menstrual function is mumps oophoritis. Three patients with premature menopause presumably caused by this agent were described. In one patient the symptoms coincided with a subclinical infection during the perinatal period, with subsequent infertility. Another patient seemed to have had a clinically mild oophoritis during the pubertal period, and the third patient became symptomatic following parturition. It appears that this aberration in menstrual function and fertility may be related to the time during which the infection occurs as well as to the severity of the infection. In addition, it is apparent that mumps oophoritis may be a more frequent cause of premature menopause than has heen previously suspected.