Tuberculosis remains one of the most serious infections after organ transplantation. Isoniazid prophylaxis for liver transplant recipients with a history of tuberculosis is generally recommended. However, its benefit is controversial because of potential hepatotoxicity of isoniazid. It is crucial to determine appropriate post-transplant managements for the recipients with a history of tuberculosis. The purpose of this study was to investigate the necessity of isoniazid prophylaxis for liver transplant recipients who had a history of tuberculosis. The medical records of 1116 liver transplant recipients were studied, of whom seven had a history of tuberculosis (0.63%). One who underwent living-donor liver transplantation for fulminant hepatic failure was excluded from evaluation because of early death, caused by bacterial sepsis two months after transplantation, although reactivation of tuberculosis was not observed. The median observation period after transplantation was 25.5 months (range 12-82). Reactivation of tuberculosis did not occur in any of these six patients. In conclusion, we could not find rationale for isoniazid prophylaxis in liver transplant recipients with past diagnosis of tuberculosis, when the disease is considered to be inactive. Tuberculosis should be considered as cause of post-transplant infections, and careful post-transplant observations are essential for an early diagnosis.