UNLABELLED: MMPs (metalloproteinases) and their inhibitor TIMP (tissue inhibitor of metalloproteinases) are important in tissue remodeling and have been implicated in nasal polyp pathophysiology. The objective of the present study was to evaluate gene expression of MMP-1, MMP-2, MMP-9 and TIMP-1 gene expression in nasal polyps and compare them with normal nasal mucosa. Since MMPs could induce a more prominent tissue edema, we also assessed if these gene expressions could be related to a more extensive disease. For the experimental study, 30 nasal polyp samples from patients with CRSwNP (Chronic Rhinosinusitis with Nasal Polyposis) and 19 middle turbinates (MT) from controls were obtained. Gene expression of MMP-1, MMP-2, MMP-9 and TIMP-1 was assessed by qRT-PCR. The expressions of these genes were compared between nasal polyps and controls and correlated to each individual Lund-Mackay score, MMP-1, MMP-2 and MMP-9 were significantly more expressed in nasal polyps than in controls (P < 0.005, P < 0.0001 and P < 0.05 respectively). No expression of TIMP-1 mRNA was detected. There was no correlation between disease extension evaluated by the Lund-Mackay score and MMPs gene expression. The present results demonstrate that there is a significantly higher mRNA gene expression of MMP-1, MMP-2 and MMP-9 in patients with CRSwNP than controls. However, no correlation was observed between MMPs gene expression and sinonasal CT scan extension. LEVEL OF EVIDENCE: 2c.