We report a case of a 65-year-old Korean female patient with rheumatoid arthritis, who presented with extensive necrotizing fasciitis of the gluteus muscles, as an unusual initial manifestation of miliary tuberculosis. The patient had been previously treated with conventional disease-modifying antirheumatic drugs and low-dose steroids for 7 years. However, she recently developed fever, warmth and painful swelling in her right buttock. Magnetic resonance imaging indicated necrotizing fasciitis of the gluteus muscles and a fasciectomy specimen revealed a Mycobacterium tuberculosis infection. Two weeks after a fasciectomy, miliary tuberculosis of the lung was diagnosed by high resolution chest computed tomography. Soft tissue infection due to M. tuberculosis should be included as a differential diagnosis in the immunocompromised host. Clinicians should be alert to the possibility of miliary tuberculosis even in the absence of respiratory symptoms and normal chest radiograph.