Background: The prevalence of diabetes in Egypt has significantly increased exceeding international rates. Egypt is now ranked ninth highest in the world in terms of the disease according to IDF, 2019. Objective: Estimation of the prevalence of gestational diabetes mellitus (GDM) in Aswan Governorate in Egypt and determination of the risk factors associated with GDM. Patients and methods: Our study was a prospective study, which carried out in the Antenatal Clinic in the Obstetrics and Gynecology Department, Aswan University Hospital from July 2016 to July 2017. The pregnant women were collected form Aswan Governorate as part of a Gestational Diabetes care in Upper Egypt project in collaboration with World Diabetes Foundation. Our study included 1000 pregnant woman. All participants were screened for GDM at 24-28 weeks of gestation. Universal screenings for GDM were performed for the participants using oral glucose tolerance test (OGTT) according to International Association of Diabetes and Pregnancy Study Groups (IADPSG) recommendations 2017. Results: According to IADPSG criteria, 17.5% of the screened cases had GDM, 16.8% had fasting blood glucose level ≥ 92 mg/dL, 15.5% had 1-hour OGTT ≥180 mg/dL and 16.7% had ≥153 mg/dL. It was found that the age ≥ 25 years and multiparity were significantly higher in GDM than in Non-GDM. Pregnant women living in rural areas and working women were significantly protected against GDM than those from urban areas. Both family history of diabetes and previous history of GDM represented the major risk factor in our studied group (P < 0.001 & < 0.001 respectively). 40.4 % of studied group exhibited no definite risk factors. There were significant increases in systolic B.P, diastolic B.P in GDM group versus non-GDM (p < 0.001 & p < 0.001 respectively). BMI was significantly higher in GDM than non-GDM (p = 0.024). Conclusion: GDM was highly prevalent in Aswan Governorate with a rate of 17.5%. The major risk factors of GDM were family history of DM and previous history of GDM, increase in age >25 and multiparity and obesity.