Despite pathophysiologic similarities, mucosal remodeling is well described in asthma but not chronic rhinosinusitis (CRS). This study attempts to identify mucosal remodeling in CRS and correlate it with clinical information. Charts and histopathology from 53 CRS patients who underwent functional endoscopic sinus surgery were reviewed. Clinical data and basement membrane (BM) thickness were recorded. BM thickness was graded as 0 (no thickening), 1 (mild thickening), 2 (moderate thickening), or 3 (marked thickening). Control mucosae from ten patients without CRS were analyzed for comparison. Duration of CRS symptoms positively correlated with BM thickness (p = 0.007). Also, patients with a markedly thickened BM (score of 3) had a significantly greater duration of CRS symptoms (120 months) compared to patients with a thinner BM (score < or =2) (33 months) (p = 0.010). Markedly thickened BM was associated with increased coincidence of asthma (p = 0.019) and aspirin sensitivity (p = 0.003). No correlation was found between BM thickness and preoperative Lund-MacKay score. There was no statistically significant difference between markedly thickened BM and thinner BM with respect to coincidence of polyps, course of preoperative systemic steroids, estimated blood loss at surgery, and number of prior surgeries. Increased BM thickness is correlated with prolonged duration of symptoms and the coincidence of asthma. This may indicate paranasal sinus remodeling akin to that which occurs in the bronchioles of persistent asthmatic sufferers.