The aetiology of Takayasu's arteritis is unknown, but an association with tuberculosis has been reported. We report the case of a 12-year-old-boy with Takayasu's arteritis: his blood pressure was 150/90 mmHg and fundoscopic examination showed grade I hypertensive changes. A tuberculin test was positive and acid-fast bacteria were seen in the urine. Angiography revealed involvement of the descending aorta, thoracic aorta and upper abdominal aorta, with fusiform enlargement and no filling of the left renal artery. He was started on prednisolone therapy, with cyclophosphamide being added subsequently. Despite vigorous treatment, including three courses of nitroprusside infusion, the severe hypertension persisted and his blood pressure became regulated only after left nephrectomy. Acid-fast bacteria were seen in the nephrectomy material. The exact role of Mycobacterium tuberculosis in the pathogenesis of Takayasu's arteritis is still unknown. In this patient the tuberculin test was positive and acid-fast bacteria were seen in both the urine and nephrectomy material. This finding is suggestive of the association between tuberculosis and the disease process.