Tuberculosis (TB) has been described in kidney transplant recipients as an infection with predominantly pulmonary involvement. We report the impact of TB in kidney transplantation. Clinical records of adult kidney recipients, transplanted between 1 January 1986 and 31 December 1995 were analyzed for sex, age, graft origin, immunosuppressive therapy, TB sites, diagnostic methods and concomitant infections. Annual incidence, mean time of onset, relation to rejection treatment, tuberculin skin test (PPD) and outcome were analyzed. Patients with a history of TB or graft loss in the first month were excluded. TB was diagnosed in 14 of 384 (3.64%). Mean age at transplantation was 35 years. Twelve of these received the graft from a living donor. All had triple immunosuppression with cyclosporine. Ten had pulmonary TB, three extrapulmonary infection and one disseminated disease. In 13 cases an invasive diagnostic procedure was performed. Mycobacterium tuberculosis cultures were positive in all cases; microscopy revealed acid-fast bacilli (AFB) in 6, and adenosine deaminase was elevated in CSF and pleural effusion in 2. Annual incidence varied from 0% to 3.1%. At the time of TB presentation 8 patients had other concomitant infections (cytomegalovirus, nocardia, Pneumocystis carinii, disseminated herpes simplex virus). Median time of onset was 13 months. Diagnostic results became available post-mortem in 2 cases, and one had TB in a failing allograft. TB was treated with 4 drugs including rifampin in 10 patients. Cyclosporine was discontinued in one, lowered in one and increased in 8. During treatment 5 patients had rejection episodes. At 1 year, graft survival was 72.7% and patient survival 90.9%. TB was more prevalent when recipient and donor were both PPD positive. In summary: although TB is a growing threat in the transplant setting, early and aggressive diagnosis with meticulous monitoring of immunosuppression allows a successful outcome for both patient and graft. Optimal prophylaxis guidelines have yet to be completely defined.