Background and study aim: Human papilloma virus (HPV) is the most common cause of cutaneous warts and mucosal papillomas and high-risk types of it are involved in developing genital, oropharyngeal, and colorectal malignancies. Interleukin-17 (IL-17), expressed by T helper 17 (Th17) cells, is crucial for inducing a protective immune mechanism against various infections. The purpose of this study was to evaluate serum IL-17 levels in patients with HPV infections compared to healthy controls. Patients and Methods: A total of 40 patients with cutaneous warts or mucous membrane papilloma and 20 healthy controls were included in this case-control study. Using enzyme-linked immunosorbent assay (ELISA) kits, serum IL-17 levels were assessed in both groups. Results: Serum IL-17 levels were significantly higher in patients with HPV infection compared to healthy controls (P=0.004). Moreover, there was a significant positive correlation between serum IL-17 level and lesion duration. Conclusions: IL-17 may play a role in the chronicity of HPV infections.