A 73-year-old immunocompetent woman was diagnosed with pulmonary nontuberculous mycobacterial (NTM) infection and followed up without treatment. She developed lumbago and consulted a physician. Spinal magnetic resonance imaging (MRI) indicated pyogenic spondylitis and she was admitted to the orthopedics department at our hospital 4 months after developing lumbago. Spinal MRI on admission revealed spondylitis in L5/S1 and thus antibiotic agents were administered. However, the antibiotics were ineffective and she underwent surgery. Mycobacterium avium complex (MAC) was identified from cultures of surgical specimens, and the histopathological findings revealed epithelioid cell granuloma with necrosis. Spondylitis due to MAC was diagnosed and the patient was administered with rifampicin, ethambutol, clarithromycin and streptomycin. She was discharged on hospital day 113 with a good outcome. Recently, the number of spondylitis due to NTM infection in immunocompetent patients have been increasing. We should take it into consideration that not only bacteria and Mycobacterium tuberculosis but also NTM infection can cause infectious spondylitis.