The purpose of this study was to evaluate visfatin levels at different stages of periodontal disease and in healthy tissues. In addition, the effect of non-surgical periodontal therapy on visfatin levels in gingival crevicular fluid and serum was investigated. Forty-five patients were divided into three groups based on clinical and radiographical findings. Group 1 comprised periodontally healthy individuals (n = 15); group 2 comprised patients with gingivitis (n = 15); and group 3 was composed of patients with generalized chronic periodontitis (n = 15). Gingival crevicular fluid and serum samples were collected before treatment and at 1, 3, and 6 months after treatment. Visfatin levels were measured by enzyme-linked immunosorbent assays. Gingival crevicular fluid and serum visfatin levels were higher in patients with chronic periodontitis than those with gingivitis or healthy controls (P < 0.016). In addition, visfatin levels were higher in the gingivitis group than in healthy controls (P < 0.016). Non-surgical periodontal treatment resulted in a significant reduction in gingival crevicular fluid and serum visfatin levels. Furthermore, visfatin levels increased with inflammation and decreased following periodontal treatment. Our findings suggest that visfatin is an inflammatory biomarker of periodontal disease.(J Oral Sci 58, 491-499, 2016).