Disseminated mycobacterial infections are becoming widely appreciated among immunosuppressed and debilitated persons. Specific microbiologic diagnosis may take several weeks, requiring empiric therapy in the interim. A case of an elderly man undergoing steroid treatment who developed spinal osteomyelitis initially thought to be caused by Mycobacterium tuberculosis is described. He was eventually shown to have infection due to M. avium-intracellulare, which requires a different therapeutic approach. The importance of considering atypical mycobacteria in systemic infections and the value of aggressive antimicrobial therapy in conjunction with a comprehensive rehabilitation program during hospitalization are emphasized in order to provide optimal management and prevent further disability.