Background:The optimal strategy for screening and diagnosis of Gestational DiabetesMellitus (GDM) is still elusive. There is possibility of difference infetaland maternaloutcome depending on the diagnostic method used. This study highlights on the efficacy of two tests 100-gram oral glucose tolerance test with Carpenter Coustan Criteria and Diabetes in Pregnancy Study Group India and to find the prevalence of GDM using DIPSI criteria and to compare the screening outcomes between DIPSI and ACOG guidelines. Methods: This study is a prospective cohort study done at tertiary care center 200 patientswhere enrolled in study between 12-16 weeks of gestation. exclusion criteria were History of GDM in previous pregnancy, known case of GDM and history of macrosomic baby. Women between 12-16 weeks of gestational age were subjected to screening for GDM by DIPSI criteria. Values more than 140 mg/dl were labelled as DIPSI positive. Positive cases were further subjected to 100gm of oral glucose tolerance test (OGTT) by Carpenter Coustan criteria at 12-16 weeks of gestation. All OGTT (Carpenter Coustan criteria) negative patients underwent repeat OGTT at 24-28 weeks of gestation. All DIPSI negative cases also underwent repeat DIPSI test at 24-28 weeks of gestation.OGTT (Carpenter-Coustan) positive cases were diagnosed as GDM and will be subjected to appropriate management. Results: The prevalence of GDM by the DIPSI test was 16% and by the Carpenter and Coustan test was 12.5%. Maximum no. cases of GDM 20 i.e. 80 % where in age group of 21-25 . 76%-19 cases of GDM where having BMI of 18.5 to 24.99 kg/m2. 14 i.e 56% GDM cases where multigravida and 11(44%) were primigravida.The sensitivity ,specificity, positive predictive value and negative predictive value were 1005,96%78.12% and100% respectively. Conclusion: DIPSI offers feasibility, convenience, simplicity and repeatability, while economizing universal screening and diagnosis of GDM .