Hyaluronic acid is a major component of many extracellular matrices and plays a central role in the homeostasis of physiology in upper and lower airways. When topically administered following endoscopic sinus surgery, hyaluronic acid may be effective in functional recovery and in the prevention of recurrence of chronic rhinosinusistis. This pilot study was aimed at evaluating the effects of nebulised 9 mg of sodium hyaluronate given for 15 days per months over 3 months in 46 patients aged greater than 4 years who underwent functional endoscopic sinus surgery (FESS) for rhino-sinusal remodelling. Eligible patients were randomized to receive nebulised 9 mg sodium hyaluronate nasal washes plus saline solution or 5 ml saline alone (23 patients in each group), according to an open-label, parallel group design, with blind observer assessment. Treatment was administered by means of a nasal ampoule that allows nebulisation of particles with a median aerodynamic diameter greater than 10 micron, i.e. suitable for upper respiratory airways deposition. The efficacy variables included clinical (presence of nasal dyspnoea), endoscopical (ostium of paranasal sinuses, oedema, respiratory patency, synechiae, and appearance of nasal mucosa) and cytological (ciliary motility and presence of neutrophils, eosinophils, mast cells, bacteria, mycetes and bio film) measures. At the end of the study, patients expressed an opinion on the overall tolerability of treatment. The two treatment groups were comparable at baseline. Treatment with 9 mg of sodium hyaluronate was associated with significantly greater improvements compared to controls in nasal dyspnoea (p less than 0.001), presence of mycetes (p = 0.044), ciliary motility (p less than 0.001) and abnormalities in nasal secretions. A univariate logistic model, in which the odd ratio (OR) indicates the probability of success in the 9 mg sodium hyaluronate group compared to the control group, showed that the highest OR was observed for presence of nasal dyspnoea (OR = 21.36; 95 percent CI: 1.07 to 426.56), normal mucosa at endoscopy (OR: 9.62; 95 percent CI: 1.82 to 50.89), ciliary motility (OR: 7.27; 95 percent CI: 1.68 to 31.42) and presence of bio film (OR: 4.41; 95 percent CI: 1.26 to 15.40). Treatment with 9 mg sodium hyaluronate plus saline was well tolerated. A 3-month intermittent treatment with 9 mg sodium hyaluronate plus saline solution nasal washes following FESS for rhino-sinusal remodelling was associated with significant improvements in nasal dyspnoea, appearance of nasal mucosa at endoscopy and ciliary motility compared to saline alone.