The difficulty in diagnosis of tuberculosis in patients with chronic renal failure or on immunosuppressive therapy is discussed. Anti-tuberculous therapy was required in 19 out of 315 patients who received a renal transplant in the Urology Unit, Hammersmith Hospital, between February 1961 and December 1979. Twelve patients were from overseas. Their management and the effect of anti-tuberculous therapy on the immunosuppressed patient were also studied. The disease was treated successfully in 18 patients, even though there were problems with diagnosis. The patient who died had active tuberculosis on post-morten examination. Prophylaxis should be considered in patients who have had tuberculosis in the past and may have received inadequate treatment.