Squamous cell carcinoma (SCC) can occur in both nonbilharzial and bilharzial bladders; the two subtypes differ in epidemiology, pathogenesis and clinicopathological features. The nonbilharzial type occurs in Western countries and represents < 5% of all vesical tumours; it occurs most often in the seventh decade with a slight male predominance. The principal predisposing factor is prolonged indwelling urethral catheterization in patients with spinal cord injury and the main symptom is haematuria. Patients are usually diagnosed at an advanced stage and most of the tumours are of moderate and high grades. At cystoscopy tumours are predominantly ulcerative and commonly involve the trigone and lateral walls. Although distant metastasis is infrequent (8-10%) the prognosis is grave and most patients die after failure of locoregional control; radical cystectomy provides the best therapy. To avoid nonbilharzial SCC, patients with spinal cord injury should be free of catheterization if possible. The outcome can be improved by early detection with frequent cytology, cystoscopy and biopsy. Bilharzial SCC occurs commonly in the Middle East, South-east Asia and South America where schistosomiasis is endemic. In an Egyptian series SCC represented 59% of 1026 cystectomy specimens. The tumour is diagnosed in the fifth decade, and five times more common in men than women. Bladder carcinogenesis is probably related to bacterial and viral infections, commonly associated with bilharzial infestation rather than the parasite itself. The presentation is often with irritative bladder symptoms and haematuria, and many patients present at an advanced stage, although most tumours are of low and moderate grades. At cystoscopy tumours are predominantly nodular and usually arise from the upper vesical hemisphere. Lymph-node metastasis occurs in approximately 19% and significantly decreases survival; radical cystectomy remains the main treatment, giving a 5-year survival rate of 50%. Early detection improves the therapeutic yield and prevention is possible by combining snail control and mass therapy of the infested rural population by oral antibilharzial drugs.