The aim of this study was to investigate serum paraoxonase (PON) and arylesterase (ARE) activities, the total oxidant status (TOS), total antioxidant status (TAS), and oxidative stress index (OSI) in the patient with nasal polyp (NP) and control group to confirm the link between oxidative stress and NP. In this prospective study, 32 patients with NP (22 males and 10 females) and 29 healthy controls (19 males and 10 females) were enrolled. Preoperative serum levels of PON, ARE, TAS, and TOS were determined, and OSI was calculated. Serum PON activity, ARE activity, and TAS tend to be decreased in patients with NP compared to healthy controls (P < 0.0001). TOS and OSI levels were significantly higher in the NP patients than in the healthy controls (P < 0.01). Furthermore, there was established positive correlation between serum PON activity and serum ARE activity in patients with NP (r = 0.454; P = 0.009). Our results support the belief that altered PON and ARE activity may be involved in the pathogenesis of NP. Increased TOS and OSI, and decreased TAS indicated that NP is the pathologic consequence of oxidative stress.