In recent years, one of the most common reasons for neuroimaging has become the evaluation of the immunosuppressed patient. In this review the radiographic appearances of the common inflammatory and neoplastic conditions affecting the central nervous system in patients with HIV infection, as well as the AIDS-dementia complex, are discussed. Non-AIDS immunocompromised neurologic disease is also examined, with particular emphasis on the effect of various immunosuppressive medications on the brain and spine.