A patient was diagnosed with discitis and sacroiliitis due to Mycobacterium xenopi. He had a history of percutaneous nucleotomy performed 15years earlier (in 1992) at the Clinique du Sport, Paris, France, during an outbreak of nosocomial M. xenopi infection at that institution. In 1997, magnetic resonance imaging performed as part of the routine follow-up program for patients who had surgery at the Clinique du Sport during the outbreak was not interpreted as indicating discitis; this assessment was confirmed by our review of the images. Bone and joint infections due to atypical mycobacteria are rare and can develop very slowly. To our knowledge, this is the first reported case of M. xenopi discitis with secondary extension to the sacroiliac joint in an immunocompetent patient.