Background: Long-term treatment outcome among patients with favorable response after successful treatment of Mycobacterium avium complex(MAC) pulmonary disease(PD) has not been evaluated and defined adequately. Methods: A retrospective review of the medical record of 276 MAC-PD patients who were treated with combination chemotherapy from 2003 to 2012 was performed. Clinical data, microbiologic study results and chest computerized tomography(CT) findings were collected on each patient. The number of involved lung segments was counted in the chest CT. Results: One hundred twenty five among 276 MAC-PD patients completed the combination chemotherapy for more than 12 months and followed up for minimal 1 year. Among these 125 patients, 97 patients(34 males, mean age 60.4) showed negative sputum microbiologic conversion and favorable response to treatment, and finally included in this study. Mean follow-up period of these 125 patients was 27.0 months. Seventy seven(79.4%) patients remained microbiologically disease-free status. Twenty(20.6%) patients recurred after successful treatment. Among 20 recurrence cases, 14 cases occurred within 12 months, and 6 cases occurred after 12 months of completing the treatment. Age, gender, and BMI were not associated with recurrence. Longer interval between diagnosis and treatment initiation( 2.88±4.65 vs. 7.20±8.21, p=0.003) bronchiectatic form(45.5% vs. 75.0%, p=0.018), increased number of lobe involvement (3.03±1.47 vs. 3.80±1.32, p=0.035), and elevated level of serum creatinine(0.79±0.18 vs. 0.91±0.14, p=0.010) were significantly associated with MAC recurrence. Sputum conversion rate within 6 months after start of treatment was higher in microbiologic disease-free than in recurrence patients(98.7% vs. 80.0%, p=0.001). Conclusions: Recurrence of MAC after successful treatment was associated with longer interval between diagnosis and treatment initiation, bronchiectatic form, increased number of lobe involvement, elevated level of serum creatinine, sputum conversion rate after 6 months of treatment initiation.