A 4-year old female with acute myeloid leukemia complicated with right calcaneal osteomyelitis due to Mycobacterium abscessus with subcutaneous abscesses extending to popliteal and groin regions after 2 courses of induction chemotherapy according to NOPHO-AML 2012 protocol. She required multiple operations and prolonged anti-mycobacterial therapy. High index of suspicion for mycobacterial infection is required for immunocompromised patients with prolonged fever or unusual presentation. Mycobacterial osteomyelitis is rare, difficult to diagnose and treat, and may necessitate prolonged interruption of anti-leukemic therapy. Multidisciplinary collaboration in patient management is crucial. Long term toxicity of antimicrobials with uncertain efficacy should not be overlooked.