Interleukin 17 (IL-17) is a Th17 cytokine associated with inflammation, autoimmunity, and defense against some bacteria; it has been implicated in many chronic autoimmune diseases including psoriasis, multiple sclerosis, and systemic sclerosis. However, whether IL-17 plays a role in the pathogenesis of ankylosing spondylitis (AS) remains unclear. To analyze the content of IL-17 and IL-23 in the serum from patients with AS compared with health control subject, 50 patients with AS and 43 healthy volunteers were recruited. Serum IL-17 levels were examined by enzyme linked immunosorbent assay (ELISA). Statistic analyses were performed by SPSS 13.0. Results show that the serum IL-17 and IL-23 levels were significantly elevated in AS patients as compared with normal controls. Nevertheless, no associations of serum IL-17 and IL-23 levels with clinical and laboratory parameters were found; no significant difference regarding serum IL-17 and IL-23 levels was found between less active AS and more active AS. However, there was a strong positive association between the serum levels of IL-17 and IL-23 in the AS patients. Our results indicate increased serum IL-17 and IL-23 levels in AS patients, suggesting that this two cytokine may play critical roles in the pathogenesis of AS. Therefore, further studies are required to confirm this preliminary data.