Osteomyelitis is a bone infection caused by bacteria or other germs. Gram-positive cocci are the most common etiological organisms of calcaneal osteomyelitis; whereas, non-tuberculous mycobacteria (NTM) are rarely documented. We reported a case of NTM calcaneal osteomyelitis in a 51-year-old female patient. She had been previously treated in many local clinics with multiple local steroid injection over 50 times and extracorporeal shock-wave therapy over 20 times with the impression of plantar fasciitis for 3 years prior. Diagnostic workup revealed a calcaneal osteomyelitis and polymerase chain reaction assay on bone aspirate specimens confirmed the diagnosis of non-tuberculous mycobacterial osteomyelitis. The patient had a partial calcanectomy with antitubercular therapy. Six months after surgery, a follow-up magnetic resonance imaging showed localized chronic osteomyelitis with abscess formation. We continued anti-tubercular therapy without operation. At 18-month follow-up after surgery and comprehensive rehabilitation therapy, she was ambulating normally and able to carry out her daily activities without any discomfort.