Background: In this study the effects of nasal septal deviation (NSD) and its surgery on nasal mucociliary clearance velocity (NMCV) in both nasal cavities were evaluated. Methods: This study included 20 patients with NSD and 20 healthy subjects as a control group who had no complaint related to the nose. NMCV was measured with rhinoscintigraphy using technetium-99m-macroaggregated albumin (Tc-99m-MAA). Results: Before the septal surgery, the NMCV of concave (10.24 ± 3.96 mm/minute) and convex sides (10.78 ± 3.53 mm/minute) of the patients were significantly lower than the control group (17.94 ± 2.89 mm/minute). There is no statistically significant difference between the NMCV of the concave and convex sides. After septal surgery, the NMCVs of the concave (16.34 ± 4.40 mm/minute) and convex sides (17.21 ± 3.43 mm/minute) were not significantly different from control groups (17.94 ± 2.89 mm/minute). Postoperative NMCVs of the concave and convex sides was significantly better than preoperative NMCVs. Conclusion: The results of this study showed that NSD significantly impaired NMCVs in both sides and that septoplasty significantly improved NMCVs in both sides. Copyright © 2007, OceanSide Publications, Inc.