A review of our records between 1993 and 1998 identified 25 patients with transitional cell carcinoma of the bladder who were less than 40 years old, 22 males and 3 females. The youngest patient was 19 years old. At the time of diagnosis 16 patients had superficial (Ta/T1) and 9 had invasive disease. Twenty-four patients were followed up for a period of 3-71 months (mean: 19.2 months). The recurrence rate for patients with superficial disease was 12.5%, and the progression rate for patients with invasive disease was 77.7%. We concluded that the patients under 30 years of age presented with lower grade and lower stage disease than those over 30. Transitional cell carcinoma of the bladder in young adults has a natural history similar to that seen in older patients. Accordingly, all patients, regardless of age, should be treated as aggressively as necessary on the basis of the stage and the grade of the tumour.