Introduction: Colouterine fistula is very rare condition that occurs mostly complicated by diverticulitis in elderly women. Other cause of colouterine fistula is sigmoid malignancy, radiotherapy, and uterine trauma. We report the case of a colouterine fistula secondary to pyometra. Case report: An 85-year-old woman with generalized abdominal pain and malodorous vaginal discharge since 2 weeks ago, visited to emergency department. She had no history of endometrial curettage and insertion of intrauterine devices. On physical examination, there are malodorous vaginal discharge. Abdominopelvic computed tomography scan showed an abscess formation within endometrial cavity and suspicious fistula formation between sigmoid colon and uterus. She underwent pelvic magnetic resonance imaging which revealed fistulous communication between distal sigmoid colon and uterine body. There are no evidence of diverticulitis in abdominopelvic CT scan, pelvic MRI. Total abdominal hysterectomy, bilateral salpingo-oophorectomy, drainage, and sigmoidectomy was performed. Also during operation, there were no evidence of colonic diverticulitis. Histopathological study of the surgical specimen revealed acute suppurative inflammation without evidence of malignancy. Discussion: Colouterine fistula is very rare condition that only less than 30 cases are reported so far. The most common cause of colouterine fistula is complication followed by colonic diverticulitis. Other causes, such as sigmoid malignancy, radiotherapy, insertion of intrauterine device, endometrial curettage, obstetrical injury, or polymyomectomy. In this case there are no evidence of diverticulitis in abdominopelvic CT scan, pelvic MRI. Also during operation, there were no evidence of colonic diverticulitis. She had no history of endometrial curettage and insertion of intrauterine devices. We report very rare case of colouterine fistular secondary to pyometra.