An increasing number of patients with human immunodeficiency virus (HIV) suffer from acute infectious sinusitis, and many suffer recurrent episodes at a higher rate than their non-HIV counterparts. This study investigates a mechanism underlying the increased incidence of sinusitis, that of prolonged mucociliary transport time (MTT). Nasal mucociliary clearance was examined in 30 HIV-infected patients and 30 matched, non-HIV controls using a nasal saccharin transport test. MTTs for the study group and the controls were 11.9 +/- 5.9 minutes and 7.4 +/- 3.7 minutes, respectively. This difference attained statistical significance (P < .05). Study group patients with a history of sinusitis had a mean MTT of 13.7 +/- 6.8 minutes. Those with complaints of "new onset" nasal obstruction since HIV conversion had a mean MTT of 13.5 +/- 6.8 minutes. Statistical significance (P < .05) was found comparing these times to controls, as well as to study patients without these symptoms. These data support an inherent delay of mucociliary clearance in HIV-infected patients which is chronic, possibly irreversible, and, in association with nasal obstruction, represents a major mechanism of both the high acute and recurrent sinusitis rate in this population. The cause of the mucociliary delay is still unclear and needs to be further investigated.