Type 2 diabetes has an insidious onset with a long latent period of dysglycaemia. By the time the diagnosis of diabetes is made, diabetes-related tissue damage occurs in nearly half of the patients. Even after diagnosis, the glycaemic control is suboptimal in more than 50%, leading to the vascular complications. Evidences suggest that early detection of diabetes by appropriate screening methods, especially in subjects with high risk for diabetes will help to prevent or delay the vascular complications and thus reduce the clinical, social and economic burden of the disease. There are also evidences to show that intervention at the prediabetic stage is superior to diagnosis of diabetes.