Background: Biologics seem to offer a promising nonsurgical approach in hidradenitis suppurativa (HS), especially in disease with highly pronounced inflammation. Recent studies revealed increased expression of a broad range of cytokines in lesional HS skin, including interleukin (IL)-17. Objective: This study was undertaken to determine IL-17 serum levels in this group of patients. Methods: Our study was conducted on a group of 86 patients between 16 and 72 years of age with HS. A total of 86 matched healthy volunteers constituted the control group. Enzyme-linked immunosorbent assay kits were used to quantify IL-17 serum concentration. Results: The mean IL-17 serum level of patients with HS was 3.68 +/- 2.08 pg/mL, which was significantly elevated (P <.0001) compared with that found in healthy volunteers (2.5 +/- 1.11 pg/mL). Moreover, there was a tendency toward higher serum concentrations of IL-17 in patients with more advanced disease (P = .005). Disease duration; patient sex, age, and body mass index; and smoking habits were not determining factors for IL-17 serum concentration. Limitations: Hospital-based study population was a limitation, as was a lack of posttreatment assessment. Conclusion: In light of our findings and literature on increased expression of IL-17 in HS lesions, evaluating the clinical effectiveness of using anti-IL-17 agents in the treatment of patients with HS is justified.