In this study, renal transplant recipients with tuberculosis of different organs, were retrospectively analysed with respect to prevalence, outcome and drug toxicity. In 520 patients, 22 (4.2%) tuberculosis of various organs was diagnosed. The time interval between transplantation and diagnosis of tuberculosis was 44.4 +/- 33.5 (range 3-111) months. In 18 (82%) of the patients, tuberculosis was detected after the first year of transplantation. The most common form was pleuro/pulmonary tuberculosis (54%), and other localizations included jejunum, liver, bone, and urogenital tract. Sixteen of the 22 patients responded favourably to the treatment and maintain excellent allograft function, whereas six patients (27.2%) died. Toxic hepatitis was seen in four (18%) patients, and one case was complicated with acute hepatocellular failure due to isoniazide (INH). However, of the 23 patients at risk of tuberculosis who had had INH prophylaxis for 1 year, neither tuberculosis, nor hepatotoxicity was observed. Tuberculosis is a common infection of renal transplant recipients in developing countries. The peak incidence is after the first year of transplantation and mortality is considerable. Hepatoxicity is a considerable risk of treatment, possibly as a result of additive toxic effects of immunosuppressive drugs.