Summary— An analysis of 58 patients who presented with their first superficial bladder tumour(s) stage Ta or T1 and who were followed prospectively is presented. Tumour characteristics which correlated well with the likelihood of new tumour occurrence were invasion of lamina propria, multiplicity, size equal to or greater than 3 cm and abnormal selected mucosal biopsies. Positive urinary cytology and higher grade tumours correlated, though less strongly. Development of higher grade or stage in subsequent tumours (i.e. progression) was associated with initial tumour multiplicity. While initial tumours were rarely found on the dome (5.2%), new tumour occurrences involved the dome in 29% of patients.