MDWD is higher in patients with wild genotypes of CYP2C9and VKORC1compared to those with variant genotypes and along with age, BMI and duration of therapy they contribute to 36.1% variability in MDWD. In future replicate study with large sample size with additional genetic factors taken into consideration needs to be carried out to develop an algorithm for determining warfarin dose before introduction into routine clinical practice. The present study provides the basic information for larger studies in our population and contributes to establish the pharmacogenetic based warfarin therapy in south Indian population.