Purpose: Transplant patients under immunosuppression are susceptible to mycobacterium tuberculosis infection. We analyzed renal transplant recipients, to evaluate the risk factors, clinical characteristics, and long-term outcomes of post- transplant tuberculosis (TB). Methods: This study is based on the records of renal allograft recipients from October 1991 to June 2006 in two transplant centers in Korea. The demographic data, clinical manifestations, and long-term outcomes of this cohort of patients were retrospectively analyzed. Results: Total 617 patients were enrolled in this study. Eighteen cases of TB (2.92%) occurred with a mean interval from transplant to diagnosis of TB of 33.1 (range: 1∼121) months. Most of post-transplant TB were pulmonary TB (including pleural) (13/18), and extrapulmonary TB occurred in 5/18. There was no difference in the prevalence of diabetes mellitus, hepatitis B or C, and immunosuppressive agents between the patients who had developed post- transplant TB and who had not. However, there was higher incidence of acute rejection in post-transplant TB group (0.9±1.1 vs. 0.4±0.6, P=0.043), and post-transplant TB group had a tendency toward more past history of TB infection (P=0.096). Thirteen patients were successfully treated, 2 patients have been under treatment and 3 patients died. The patient survival was significantly reduced by post- transplant TB in multivariate analysis (relative risk=3.355, P=0.038). Conclusion: Post-transplant TB is a serious problem, which is associated with poor outcomes in renal transplant patients. Therefore, high index of suspicion is warranted to ensure early diagnosis and prompt initiation of treatment.