Background: An elevated HbA1c has been associated with a significantly increased risk of many adverse obstetric outcomes including congenital anomalies, spontaneous abortions, preeclampsia, and large for gestational age infants at birth. Objective: This study aimed to predict adverse obstetric and neonatal outcomes in pregestational diabetic pregnancies. Patients and method: The study included 72 pregnant diabetic women in the third trimester of pregnancy (28 weeks to 40 weeks) divided into two groups; Good glycemic control group (Hb A1c <6.5%) (n=30), and poor glycemic study group (HbA1c >6.5%) (n=42). Participants were followed up till delivery and maternal and perinatal outcomes were studied. All participants were subjected to careful history taking, through clinical and obstetric examination. The newborns were examined, and their conditions were assessed by pediatricians. Result: There was a statistically non-significant association between glycemic control of the studied patients and mode of delivery; Poor glycemic study group had 35 (83.3%) cesarean sections (CS) versus 20 (66.7%) CS in good glycemic control group. There was a statistically significant association between glycemic control of the studied patients and body mass index. There was a statistically significant association between glycemic control of the studied patients and parity which was significantly higher in those with high parity. There was a statistically non-significant association between glycemic control of the studied patients and their age, gravidity, history of abortion, IUFD or macrosomia. Conclusion: Antenatal HbA1c values are useful to predict adverse obstetric and neonatal outcomes, especially preterm delivery and hyperbilruinemia in pregnancies complicated by pregestational diabetes. Also, antenatal HbA1c values are useful for objective risk stratification of patients with pregestational diabetes.