Mucociliary clearance is one of the homeostatic systems of the respiratory mucosa. Alterations in mucociliary clearance have been extensively studied in asthma, but less frequently in allergic rhinitis. In rhinitis, conflicting results have arisen: while some authors reported no change, others noticed a reduction in nasal mucociliary clearance. The aim of this study was to compare the nasal mucociliary clearance in allergic and non-allergic patients with perennial rhinitis and a healthy control group. One hundred and three patients and 14 healthy control subjects were studied. Nasal mucociliary clearance was assayed with the saccharin test modified with a food dye to add a visual parameter. Patients were divided into allergic and non-allergic rhinitis according to the presence of three of the following factors: total serum IgE above 180 KIU/L, positive skin prick tests to a battery of standardized allergens relevant to Uruguay, family and personal history of atopic diseases, and blood eosinophilia above 450 cells/mm3. The aspect of the nasal mucosa was not considered for categorizing the patients. Fifty-seven patients (29 males, mean age: 22.2 years) with allergic perennial rhinitis and 46 patients (15 males, mean age: 24.8 years) with non-allergic perennial rhinitis were compared with 14 controls (6 males, mean age: 35 years). A significant difference in nasal mucociliary clearance was observed between the three groups, with a mean of 8.8 minutes for the controls, 10.27 minutes for allergic rhinitis and 11.73 minutes for non-allergic patients. We suggest that the differences we observed were due to changes in the rheology of nasal mucus as a consequence of the underlying inflammatory process in rhinitis.