Magnetic resonance images (MRI) of the brain from 75 homosexual men were reviewed to evaluate the frequency and severity of incidental sinus disease associated with human immunodeficiency virus (HIV). All scans had been performed for reasons other than a history of sinus disease. The opacification of each sinus cavity was scored such that 0 = normal, 1 = < 25%, 2 = 25% to 75%, and 3 = > 75% opacification. Subjects were then stratified by clinical status into four groups: HIV-, HIV+ without HIV-related symptoms, AIDS-related complex (ARC), or AIDS. Grade 1 mucosal thickening was present in 52% to 55% of HIV- and HIV+ subjects alike. Moderate disease (grade 2 or 3) was seen in seven of 52 HIV+ subjects, but none of the 23 HIV- controls. The incidence of maxillary sinus thickening was 69% in men with AIDS, compared to 30% in HIV- men (chi 2 = 4.1, p < 0.05). Mean maxillary sinus scores were 1.25 +/- 0.29 in those with AIDS compared to 0.43 +/- 0.15 in HIV- men (f = 5.11, p < 0.05). Our results suggest that maxillary sinus disease is more common and more severe in patients who have AIDS.