BACKGROUND Periodontitis is a chronic inflammatory disease which is multifactorial. Diabetes mellitus (DM) is one of the major systemic factors to influence the severity of chronic periodontitis. Numerous inflammatory markers are produced in the course of the disease which is secreted in saliva too. This study evaluates the salivary concentrations of interleukin-6 (IL-6) in periodontitis patients with type 2 diabetes. MATERIALS AND METHODS Whole saliva samples were collected from eighty patients who were further divided into four groups; healthy (control group; n = 20), untreated periodontitis (UPD; n = 20), DM (DM; n = 20), and UPD + DM (n = 20 groups). Salivary IL-6 concentrations were determined by standard enzyme-linked immunosorbent assay. RESULTS Results show that the UPD patients with and without DM exhibited higher concentrations of salivary IL-6 than the control group and diabetes groups. Further, the salivary IL-6 was correlated with glycosylated hemoglobin A levels in patients with diabetes. CONCLUSION Concentration of salivary IL-6 was elevated in patients with periodontitis with and without diabetes. Thus, salivary IL-6 levels can be considered as an important biomarker in the diagnosis of periodontitis and diabetes.