A case of Müllerian adenosarcoma of the uterus is described. The patient, an 81-year old female, was treated in hospital for vaginal bleeding in 1993. She was diagnosed as having a tumour of the uterus. The patient underwent an abdominal hysterectomy with bilateral salpingo-oophorectomy. We found a polypoid intrauterine tumour which had led to a swelling of the cavum and cervical canal. Histologically a Müllerian adenosarcoma was diagnosed. The tumour consisted of a benign glandular component and an mesenchymal component in the form of a low differentiated pleomorphic rhabdomyosarcoma.