Background: Chronic periodontal disease is an infectious inflammatory disease and type 2 diabetes mellitus is a metabolic disease due to disrupted insulin action. The present study was conducted to assess serum interleukin- 10 levels in chronic periodontitis and type II diabetes mellitus patients. Materials & Methods: The present study was conducted on 84 patients divided into 4 groups of 21 each: Group I (healthy controls), group II (CPD only) were nondiabetic and systemically healthy and diagnosed with periodontal disease; group III (T2DM with CPD) were diagnosed as type 2 diabetes with periodontal disease and group IV (T2DM without CPD) were diagnosed as type 2 diabetes with no evidence of CPD. Parameters such as plaque index (PlI), gingival index (GI), PPDs, clinical attachment loss (CAL), bleeding on probing (BoP), BMI, radiographic evidence of bone loss, glycated hemoglobin (HbA1c) levels, serum IL-10 and random blood sugar levels was assessed. Results: The mean PI in group I patients was 0.21, in group II was 1.64, in group III was 1.82 and in group IV was 0.20. Gingival index was 2.2 in group II, 2.48 in group III, bleeding on probing (BOP) was 0.30 in group I, 2.70 in group II, 2.90 in group III and 2.32 in group IV, PPD was 1.04 in group I, 5.72 in group II, 5.82 in group III and 0.98 in group IV and AL was 1.82 in group II and 2.56 in group III. The mean HbA1C value in group I was 4.82, in group II was 5.72, in group III was 8.92 and in group IV was 7.91, random blood sugar was 112.8 in group I, 104.6 in group II, 224.6 in group III and 212.6 in group IV. IL- 10 level was 15.6 in group I, 10.2 in group II, 11.4 in group III and 12.6 in group IV. The difference was significant (P< 0.05). Conclusion: Authors found that low IL-10 level is associated with high HbA1c. Serum IL-10 levels may be one of the predictors of glycemia. Key words: Bleeding on probing, Diabetes mellitus, Periodontal disease