The purpose of this paper was to evaluate the level of Cyclooxygenase-2 (COX-2), Periostin (POSTN) and Interleukin-4(IL-4) gene expression in patients with chronic rhinosinusitis with nasal polyps, without polyps and with a nasal septum deviation. The tests were performed on 63 patients (24 women and 39 men) with chronic rhinosinusitis and polyps (CRSwP-study group I), with determination of the COX-2, POSTN and IL-4 gene expression; an allergy was diagnosed in 38 cases. The reference groups were patients with chronic rhinosinusitis without polyps--CRS (n = 23, including 14 women and 9 men) and patients with nasal septum deviation--DSN (n = 18, including 9 women and 9 men). The expression level was determined in the polyp tissue and the mucosa of paranasal sinus collected during an FESS. The expression level of studied genes was also evaluated in the material. Immediately after being collected, the tissue fragments were placed in test tubes with 1 ml of RNAlater (Qiagen, Hilden, Germany) preventing the degradation of RNA and frozen at -70 °C. The studies revealed an increased level of POSTN, IL-4 gene expression and a decreased level of COX-2 gene expression that may be associated with the development of chronic rhinosinusitis with nasal polyps. An analysis of the expression level indicates the participation of POSTN and IL-4 in the development of chronic rhinosinusitis with nasal polyps in patients with atopy.