Aim: Chronic periodontal disease (CPD) and type 2 diabetes mellitus (T2DM) share common pathogenic pathways involving the cytokine network resulting in increased susceptibility to both diseases, leading to increased inflammatory destruction, insulin resistance, and poor glycemic control. Periodontal treatment may improve glycemic control. The aim of this study was to evaluate the effect of scaling and root planing (SRP) of T2DM patients with CPD on hyperglycemia and the levels of serum interleukin-10 (IL-10). Materials and Methods: Forty-five subjects were divided into three groups comprising 15 subjects each as Group 1 (healthy controls), Group 2 (CPD patients), and Group 3 (T2DM patients with CPD). Plaque index, gingival index (GI), probing pocket depths (PPD), clinical attachment loss (AL), bleeding on probing (BoP), random blood sugar, glycosylated hemoglobin (HbA1C), and serum IL-10 were measured at baseline; SRP was performed on Groups 2 and 3 and the selected parameters recorded again at 6 months. Results: Statistically significant (P < 0.05) differences were observed in the variables at baseline and 6 months after SRP between the three groups using one-way ANOVA. The paired samples t-test for PPD and AL in Group 3 was statistically significant. Group 3 revealed positive correlations between PPD and HbA1C, BoP and IL-10, respectively, at 6 months and a predictable association of HbA1C with PPD and GI, and IL-10 levels with BoP, respectively, at 6 months. Conclusion: Scaling and root planing is effective in reducing blood glucose levels in T2DM patient with pocket depths and effective in elevating systemic IL-10 levels in CPD patients and CPD patients with T2DM.