Nontuberculous mycobacterial infections are rare but severe complications of chemotherapy in children. In children with prolonged lymphopoenia after mieloablative regimens, symptoms can be nonspecific and fever and pulmonary impairment are the most common clinical features. Diagnosis is challenging for physicians and microbiologists and often requires invasive techniques. We report a girl affected by acute lymphoblastic leukemia, who developed a disseminated infection sustained by Mycobacterium avium complex. Identification of the microorganism was obtained by open lung biopsy and evidence of mycobacterium genome. We also reviewed 15 literature cases of disseminated infections of nontuberculous mycobacterium in children with leukemia.