Objective: Malignant fibrous histiocytoma (MFH) is an extremely rare malignant mesenchymal neoplasm of the urinary bladder with only a few well-documented cases reported in the English literature. Method: We report the case of an 88-year-old man who was brought to our hospital due to sudden massive haematuria. Catheterization failed to obtain haemostasis so, a suprapubic incision and direct exploration of the bladder was performed. A large solid tumor was found with a shaggy haemorrhagic surface and biopsies were taken. Results: Histological examination revealed an infiltrating malignant neoplasm composed of variably pleomorphic ovoid neoplastic cells with eosinophilic cytoplasm, bizarre tumor giant cells and prominent stromal osteoclastic giant cell reaction. Immunohistochemical examination was negative for cytokeratin, desmin, smooth muscle actin, PSAP, NSE, S100protein and HMB45 whereas it was positive for CD68 in a large number of tumor cells. Accordingly, the diagnosis of undifferentiated pleomorphic sarcoma with histological features compatible with giant cell MFH of the urinary bladder was made. The patient died 4 days after the diagnosis. Conclusion: In conclusion, MFH of the bladder should be kept in mind when facing with an undifferentiated malignant tumor. Despite the poor prognosis, early diagnosis and aggressive salvage therapy might offer the chance of long-term survival in selected cases.