Mycobacterium kansasii is a common cause of pulmonary infection as a result of nontuberculous mycobacteria, but is less commonly described as a cause of an orthopedic infection. We present the first case of M. kansasii subacromial septic bursitis in an immunocompromised host. This case demonstrates the diagnostic and treatment challenges associated with orthopedic infections caused by M. kansasii.