A 33-year-old woman was referred to us by the department of urology because of cyclic bladder pain during menstruation. Cystoscopy showed a 3.5-cm-diameter tumor in the bladder mucosa, and a biopsy showed chronic cystitis. Transvaginal ultrasound and pelvic magnetic resonance imaging revealed a left endometrial ovarian cyst. Although a biopsy did not prove bladder endometriosis, we diagnosed bladder endometriosis on the basis of the characteristic clinical findings. Laparoscopic partial cystectomy for bladder endometriosis and left ovarian endometrial cyst resection were performed. The bladder was closed in one layer using Z sutures with #3-0 polyglactin 910. Indigo carmine dye was then used to check for any leakage. The procedure lasted 4 hours, and the estimated blood loss was 10mL. There were no technique problems or complications. The Foley catheter was removed after 7 days. The symptoms had resolved by 4 weeks after surgery, and the patient was released to routine follow-up. The patient had complete resolution of bladder symptoms and cyclic pelvic pain and was delighted with the absence of pain and the cosmetic result.