We report two cases of pulmonary tuberculosis in heart transplant recipients: a 46-year-old man with pulmonary tuberculosis due to Mycobacterium tuberculosis and a 64-year-old man with nontuberculous mycobacterial infection with pulmonary infiltrates due to Mycobacterium xenopi. The time intervals from transplantation to diagnosis were 3 and 4 years, respectively. The patient with tuberculosis underwent standard treatment with isoniazid, rifampin, ethambutol, and pyrazinamide. The patient with the nontuberculous mycobacterial infection received treatment with clarithromycin and ciprofloxacin for 18 months in addition to rifampin for the first 3 months. Both patients responded well to treatment. No recurrences were observed during follow-up. The interactions between antibiotic treatment and cyclosporine therapy should be observed closely in organ transplant recipients, requiring frequent level determinations and dosing changes.