Tuberculosis developed in 40 out of 978 chronic renal failure (CRF) patients with or without renal replacement therapy during a five-year period. The incidence was 4.1% and was 10 times higher than that in the general population. The onset of symptoms was within 1 year after dialysis or kidney transplantation in 68% of the patients. 82.5% of them had predominantly extrapulmonary tuberculosis and most of these were lymph node infection. The diagnosis of tuberculosis in these patients was difficult; tuberculin sensitivity was present only in 6.4% of the patients and examination of sputum and other fluid for mycobacteria was usually unrewarding. Detecting serum anti-PPD-IgG level might be a valuable supplementary diagnostic method, because 85% of patients with active tuberculosis showed positive results. Measuring serous exudate and urine anti-PPD-IgG level by ELISA or M. Tuberculosis DNA by PCR might be helpful in the diagnosis of tuberculous serositis and urinary tract mycobacterial infection.