Mycobacterium chelonei was isolated from a breast abscess in a healthy 46-year-old non-lactating Caucasian woman. In-vitro testing showed the organism to be resistant to conventional anti-tuberculosis agents but sensitive to tetracycline and erythromycin. Treatment with isoniazid, pyrazinamide and rifampicin initially produced a good response but the subsequent development of multiple abscesses required the addition of tetracycline and finally a change to erythromycin and trimethoprim, on which recovery was complete.