The aims of the present study were to determine the gingival crevicular fluid (GCF) chemerin and interleukin-6 (IL-6) levels and to analyse the relationship between chemerin and IL-6 in periodontal health and in chronic periodontitis (CP) with and without type 2 diabetes mellitus (T2DM) as well as to evaluate the effect of non-surgical periodontal therapy on the GCF chemerin levels.