Although malignant fibrous histiocytoma is the most common among soft tissue tumours in adults, its origin in the bladder is extremely rare. Only 17 cases have been reported so far. We present the case of an 86-year-old patient who, following clinical and instrumental examination for a large bladder growth, underwent partial cystectomy. The histopathological exam showed a neoplastic mass, while immunohistochemical findings indicated a malignant fibrous histiocytoma. A transitional cell carcinoma in situ with microinfiltration of the lamina propria was also observed near the above tumour.