Mucociliary clearance of the nasal cavity is an important defence mechanism of the body. This is associated with the pathologic conditions of the nose and paranasal sinuses. Mucociliary clearance can be measured by the radioactive particles, aluminium discs, saccharin particles and photoelectric method et al. Among them the saccharin method is a simple non-invasive screening method. Authors measured mucociliary clearance time by the saccharin method in patients with chronic sinusitis with or without nasal polyp before and after functional endoscopic sinus surgery(FESS) or Caldwell-Luc's operation from 1992 to 1992. And authors studied mucociliary clearance time of the normal control group to compare to that of patient groups. All patients had preoperative, 2nd, 4th, 8th, 12th, and 24th week postoperative assessments respectively. The results of this study were as follows : 1) Mucociliary clearance time of the normal control group(eighty cases) was 8.3±1.9 minutes. 2) Mucociliary clearance time of the group with chronic sinusitis with or without nasal polyp was more significantly increased than that of the normal control group(p<0.01). 3) Mucociliary clearance time of the group treated with FESS recovered gradually from second week postoperatively(p<0.01). 4) Mucociliary clearance time of the group treated with Caldwell-Luc's operation at second week postoperatively was prolonged than that of the preoperative state, and that was gradually improved after eighth week postoperatively. 5) There was no statistical difference between mucociliary clearance time at twenty-fourth week after the operation and that of the normal control. In conclusion, mucociliary clearance time of the group treated with FESS recovered earlier than that of the group treated with Caldwell-Luc's operation.