Background: The prevalence of tuberculosis in heart transplant recipients has been known to be higher than that in the general population. However, indications for prophylaxis and its outcomes are uncertain in endemic regions such as South Korea. Methods: The medical records of 244 patients who underwent heart transplantation during a 17-year period from Jan 1992 to Jan 2009 at Asan Medical Center were reviewed and analyzed. Indications for prophylaxis included a history of tuberculosis infection and radiographic evidences of previous infection at the time of transplantation. Tuberculin skin tests were not routinely performed because of high incidence of positive test and previous BCG inoculation. The prophylactic agent was isoniazid. Results: Twenty patients received isoniazid prophylaxis. 15 were men and a median age was 48.0짹8.5 years (range: 30 to 69). The duration of isoniazid prophylaxis was 9짹3 months (range: 4 to 12). 12 patients who had radiographic abnormalities took isoniazid for 12 months except 2 patients. One had just fungal ball in chest radiograph and received 6-month prophylaxis. The other stopped it due to hepatotoxicity. 5 patients had a history of tuberculosis infection and also received 12-month prophylaxis except 1 patient. Other causes of prophylaxis were as follows: persistent pericardial effusion after transplantation (n=2), cases of heart-kidney transplantation (n=2), and strongly-positive tuberculin test (n=1). Tuberculosis was proved in 6 patients (2.5%). There was no development of tuberculosis infection in prophylaxis group. The median time from the transplant to the development of tuberculosis was 20.6짹11.7 months (range: 6.5 to 39) and the mean time from symptoms to the diagnosis was 19.3짹8.6 days (range: 10 to 28). Fever was the most common symptom (n=3), but asymptomatic effusion or chest infiltrations on radiograph were also detected. Tuberculosis infection included pulmonary tuberculosis (n=2), pericarditis (n=2), and miliary tuberculosis (n=2). 4 patients had no comorbidity. 5 patients were treated with a 4-standard regimen for a mean duration of 9.6짹2.5 months. There was no tuberculosis-related mortality. Conclusion: There have been few reports on the duration or indication of tuberculosis prophylaxis after heart transplantation in endemic areas. In this study, most patients received 12-month isoniazid prophylaxis when the indication based on history or radiographic findings was satisfied and this showed great outcomes. In addition, appropriate diagnosis and treatment of tuberculosis infection would be important because it is difficult to predict tuberculosis infection beforehand.