Adenomyolipoma of the uterus is a rare, benign, polypoid lesion considered to be of hamartomatous origin or represent an unusual type of benign Mullerian mixed tumour with a heterologous element. The authors present a case of uterine adenomyolipoma and discuss its pathogenesis. A 62-year-old woman complained of lower abdominal pain and post-menopausal bleeding. Imaging techniques revealed a solid ovarian mass and a polypoid intrauterine lesion. The frozen section diagnosis of the ovarian mass was a thecoma. A total hysterectomy and bilateral salpingo-oophorectomy were performed. On gross examination a pedunculated, polypoid lesion of 7x4.5x3 cm was found in the uterine cavity. Microscopically, the polypoid lesion contained both epithelial and mesenchymal elements. The epithelial elements were endometrial glands of various size, formed by proliferative endometrial cells. The mesenchymal elements were composed of endometrial stroma, smooth muscle and mature adipocytes. Both the epithelial and the mesenchymal elements showed a benign appearance, were intermingled with each other and periglandular stromal condensation was absent. The lesion had an irregular surface. Microscopic diagnosis was an adenomyolipoma. The peculiar shape and microscopic features of this lesion suggested that it was a variant of benign Mullerian mixed tumour.