There is general agreement that there is a significant relationship between diabetes and periodontitis. Many studies have shown a high prevalence of periodontitis in diabetic patients. In addition a higher prevalence and more aggressive periodontitis are found in patients with poorly controlled diabetes. The duration of having diabetes is an important factor that affects the progression and severity of periodontitis. Alterations in the host response in diabetics to existing periodontal pathogens may be primarily responsible for the more aggressive periodontal destruction observed in patients with diabetes. Diabetes is characterized by hyperglycemia, which affects the host response by several mechanisms: AGE accumulation, vascular alteration, changes in oral environment due to increased glucose concentration in GCF resulting in shifts of the microbial flora and altered cell function like PMNs, fibroblasts and monocytes. These changes may lead to prolonged inflammation and impaired wound healing. Periodontitis may alter glycemic control and increase the risk of progression of diabetic complications and increase the mortality rate of diabetes. The mechanism behind this is the increasing levels of inflammatory mediator TNF-á which increase insulin resistance leading to poor glycemic control. Treatment of diabetic patient is highly dependent on the degree of glycemic control. Well controlled diabetics can be treated as non-diabetics, but the risk of peroperative hypoglycaemia should be considered. Conventional periodontal therapy combined with antibiotics may enhance glycemic control in poorly controlled subjects.Patients with previously undiagnosed type 2 diabetes may have several intraoral signs like multiple periodontal abscesses, exophytic tissue extending from periodontal pocket, mobile teeth and severe bone loss etc. The referral of these patients to the physician may help in early diagnosis.