Background: Gestational diabetes is diabetes, or high blood sugar levels, that develops during pregnancy.  It occurs in about 4% of all pregnancies. It is usually diagnosed in the later stages of pregnancy and often occurs in women who have no prior history of diabetes. Aim of the Work: To assess the predictive value of elevated glycosylated hemoglobin at 34 weeks' gestation with adverse fetal outcome as regard fetal macrosomia and neonatal hypoglycemia. Patients and Methods: This prospective longitudinal cohort study included 98 pregnant women who were recruited from the obstetric outpatient clinic and department at Al-Galaa Teaching Hospital. Results:  HbA1c ≥7.9 has sensitivity of 88.1% and specificity of 66.1%, in prediction of macrosomia and a sensitivity of91.9% and specificity of 63.9% in prediction of Hypoglycemia. Conclusion: HbA1c ≥7.9 has moderate diagnostic characteristics in prediction ofmacrosomia, and hypoglycemia, low diagnostic characteristics in prediction of RDS and NICU. Recommendations: Use of HbA1C is recommended for patients with GDM for screening, follow up and prediction of adverse neonatal outcomes.