Introduction: Gestational diabetes mellitus (GDM) is a potentially serious and prevalent condition such as fetal growth abnormalities, shoulder dystocia, birth injury, prematurity and increased Caesarean section rate, which may lead to serious effects in mothers and neonates. Recently HbA1c used diagnostic criterion for diabetes (DM). Objective: Diagnosis and Management of Gestational Diabetes with Oral Glucose Tolerance Test and Hba1c. Methods: A total of 241 pregnant women recruited in the study. Pregnant women in prenatal care, without previous DM, were included to perform OGTT tests in the third trimester of pregnancy. written informed consent was obtained from all the patients. Results: All the patients were between 23 and 35 years of age in the third trimester of pregnancy (gestational age = 27__ampersandsignplusmn;5 weeks). In patients without GDM mean SBP was 110__ampersandsignplusmn;11.8and with GDM 119__ampersandsignplusmn;12.6 (p __ampersandsignlt;0.001). In cases without GDM mean DBP ( Diastolic blood pressure) was 70__ampersandsignplusmn;8.4 mmHg and with GDM 82__ampersandsignplusmn;15.1 mmHg (p __ampersandsignlt;0.001). In patients without GDM mean FBS (Fasting blood sugar) was 77.4__ampersandsignplusmn;9.4 and with GDM 95.4__ampersandsignplusmn;12.6 mg/dl. Mean 1hrs. Glucose was 120.6__ampersandsignplusmn;12.4 in patients without GDM and with GDM it was 176.8__ampersandsignplusmn;16.4. In patients without GDM mean 2HRS.Glucose was 115.2__ampersandsignplusmn;11.4 and with GDM 147__ampersandsignplusmn;15.4. In patients without GDM mean HbA1c was 5.2__ampersandsignplusmn;0.3and with GDM 5.9__ampersandsignplusmn;0.6 (p __ampersandsignlt;0.001). In patients without GDM mean Hb was 11.6__ampersandsignplusmn;0.7and with GDM 11.8__ampersandsignplusmn;0.5 (p 0.022). In patients without GDM mean Cholesterol was 210__ampersandsignplusmn;22.4 and with GDM 225__ampersandsignplusmn;35.7 (p __ampersandsignlt;0.001). Conclusion: Different HbA1c cut-off points may be useful in a diagnostic tool for GDM in combination with OGTT. This will result in a considerable decrease in the research workload on both patients and the testing centre, employees and equipment.