A wide variety of neurologic complications associated with human immunodeficiency virus-type 1 (HIV-1) infection result from HIV-1 itself or secondarily related to immunosuppression. In Korea, the number of HIV-1 seropositive populations is increasing, but little has been known about the neurologic complications of HIV-1 infection. To investigate the neurologic complications in HIV-1 infected Korean patients, we performed a cross-sectional study in consecutive admissions to the Seoul National University Hospital between March 1998 and June 1999. Thirty-four HIV-1 seropositive patients were included. As a result, a total of 26 HIV-1 related neurologic complications were identified from 17 patients. Among them, 10 patients showed cognitive/motor abnormalities: 3 HIV-1-associated dementia and 7 possible HIV-1-associated minor cognitive/motor disorder. Neuromuscular complications were found in 10 patients: 9 distal symmetric polyneuropathy, and 1 possible chronic inflammatory demyelinating polyradiculoneuropathy. In 3 patients with focal brain lesions, 2 were presumptively diagnosed as having primary CNS lymphoma, and 1 as having progressive multifocal leukoencephalopathy in the posterior fossa, based on history, clinical findings, serology, radiological appearances, and response to empirical therapy. Other complications included cryptococcal meningitis and only soft neurologic signs without any neurologic disease. Most of these complications (88%) occurred in the advanced stage of infection.