Mycobacterial species other than Mycobacterium tuberculosis and Mycobacterium leprae constitute nontuberculous mycobacteria (NTM). NTM infections are on the rise, particularly in the Western world. They cause a wide range of pulmonary and systemic manifestations. The 2 most common types are as follows: classical cavitary type, seen with preexisting lung disease, and the nonclassical bronchiectatic type, seen in elderly women without preexisting lung disease. Disseminated infections by the hematogenous route are common in immunocompromised patients including those with HIV. Imaging plays a key role in the diagnosis and monitoring of NTM infection.