We present a case of a patient with a rare case of atraumatic Mycobacterium avium-intracellulare complex lumbar osteomyelitis and epidural abscess with acute spinal cord compression. She presented to the emergency room with a 2-month history of progressive, bilateral hip and leg pain, with progression to an inability to ambulate. A magnetic resonance imaging of the lumbar spine revealed an epidural mass at L1 and associated compression of the conus medullaris. The patient was taken for decompression of the lumbar mass via a T12–L1 laminectomy. Approximately 6 weeks later, the final culture yielded M. avium-intracellulare complex epidural abscess. Mycobacterium avium-intracellulare complex–associated musculoskeletal infection is extremely rare, and to date, we have identified only 8 other cases in the literature. This case presentation will add to existing literature and highlight the continued need to consider atypical mycobacterial infection as a cause of unremitting back pain in immunocompromised individuals.