Type 2 diabetes is a complex multifactorial disease characterized by insufficient insulin secretion and insulin resistance. Global prevalence of diabetes is increasing day by day making diabetes a global epidemic. Various factors increase risk of diabetes and genetic predisposition is one of vary important factor. Many anti- diabetic treatments are available to control blood glucose levels in diabetic patients. Now-a-days initially, oral antidiabetic treatment is successful but it fails later on and requires insulin administration and there are large numbers of non responders also. Even patients that do respond show variability in drug response and tolerance. Pharmacogenomics is the study to determine the inter-individual differences that contribute toward drug response. Many studied have shown positive contribution of different polymorphism in alteration of drug response in various ethnicities but still data related to pharmacogenomics of asian population is limited. In this review, we have tried to summarize the genetic variations and their effect on 3 major classes of oral antidiabetic medications that include thiazolidinediones, metformin and sulfonylureas