Of 27 women in the reproductive age group receiving continuous ambulatory peritoneal dialysis for more than 3 months, 4 of 7 who menstruated developed recurrent hemoperitoneum. Tubal ligation had been done in 3 of these 4 women. There were 37 episodes of hemoperitoneum; 22 occurred at midcycle and 15 with menstruation. One patient required repeated blood transfusion, but after oral anovulant therapy no further bleeding occurred and no transfusion was required. Two patients needed laparotomy: one for heavy intraperitoneal bleeding originating from a luteal cyst, and the other for severe lower abdominal pain from follicular and luteal cysts. Ultrasound examinations suggested the presence of small ovarian cysts in the two remaining patients. Recurrent midcycle hemoperitoneum in women on continuous ambulatory peritoneal dialysis may be triggered by ovulation and associated ovarian cyst formation. Suppression of ovulation should be considered.