Even though the majority of patients with bladder malignancies initially present with low stage disease, the clinical epidemiology of these so-called superficial bladder tumours is not well known. In this paper, disease characteristics at initial presentation and during follow-up are described in 1,745 primary cases documented prospectively in the Netherlands. The risk of recurrent disease after primary treatment is very high: in 60% of cases, at least one recurrence is diagnosed within 5 years (95% CI: 58-62%). In patients with a small solitary pTa grade 1 tumour, the 3-year recurrence risk is 37%. In patients with multiple large high grade pT1 tumours, this risk is as high as 77%, despite a significant beneficial effect of adjuvant intravesical chemotherapy. The actuarial risk of disease progression is 10.2% after 3 years (95% CI: 8.6-11.8%). This risk of progression depends on the patient's age at diagnosis, tumour stage, grade, multiplicity and the presence of dysplasia or CIS in random urothelium biopsies. The use of intravesical instillations with chemotherapy or BCG vaccine after TUR does not prevent progressive disease, although this finding is difficult to interpret from a non-randomised study. The 5-year relative survival in patients with superficial TCC of the bladder is 86% (95% CI: 84-88%).