As part of a prospective multidisciplinary study of individuals seropositive for the human immunodeficiency virus (HIV), cranial magnetic resonance (MR) imaging was performed on 119 HIV-seropositive subjects (95 asymptomatic, 24 symptomatic) and the results were correlated with clinical data. MR images regarded as positive included those showing atrophy and/or white matter lesions. On the basis of these criteria, 96 subjects had normal MR images and 23 had abnormal images. Results of chi 2 analysis revealed a statistically significant difference between the asymptomatic group (12 of 95 [13%] with abnormal scans) and the symptomatic group (11 of 24 [46%] with abnormal scans) (P = .001). In the asymptomatic group, positive MR images showed fewer, smaller, and/or less extensive abnormalities. The researchers conclude that (a) MR imaging can show indirect evidence of HIV infection early in the disease, but abnormalities will be minor and seen only in a small minority of neurologically asymptomatic subjects; (b) the appearance of clinically recognizable neurologic disease correlates with the MR imaging findings of increasingly severe brain atrophy and white matter lesions; and (c) in some HIV-seropositive subjects, despite neurologic disease, MR images can remain normal. Results indicate that routine screening with cranial MR imaging of neurologically asymptomatic HIV-seropositive individuals would likely result in a low yield of positive findings.