The prevalence of pulmonary Mycobacterium avium complex (MAC) disease in the elderly population is expected to increase. However, there are few reports on the effectiveness and tolerability of standard chemotherapy in elderly pulmonary MAC patients. To investigate the effectiveness and tolerability of standard chemotherapy in pulmonary MAC patients over 75 years old, we retrospectively examined the differences in clinical course between a treatment group and an observation group, and between those aged 75–79 years old and those over 80 years old in the treatment group. Among the 61 elderly patients included, 33 patients started standard chemotherapy and 28 patients were under observation without treatment. Twenty-six patients (78.8%) could continue treatment for more than 12 months with a continuous rate of 85.7% at the age of 75–79. Significant image (p<0.0001) and symptom (p=0.0003) improvement were observed in the treatment group. Most elderly pulmonary MAC patients tolerated the standard treatment and experienced improvement of imaging studies and symptoms.