The natural history of superficial bladder carcinoma has an important bearing on the outcome of response to intravesical chemotherapy or immunotherapy. It may vary in different parts of the world, but it is essential that urologists know within their own practice how tumours respond to the initial transurethral resection. Many factors influence the natural history of superficial bladder carcinoma, and some, such as poor-grade, large tumour at presentation, smoking history, poor response to initial resection, and dysplasia or carcinoma in situ, should alert the urologist to introduce intravesical therapy at an early stage.