Diabetes mellitus is one of the most common pre-existing maternal disorders and complicated approximately 1.3% of all pregnancies Most women with pre-gestational diabetes (PGD) characterized by disturbance in glucose metabolism may be due to variable degrees of insulin resistance (type 2), or a consequence of autoimmune destruction of the pancreatic β-cells (type 1). Furthermore, PGD has also been associated with increased risk of maternal complications including shoulder dystocia, gestational hypertension, and pre-eclampsia , making pre- pregnancy care particularly glycaemic control and obstetrical interventions of great importance. The aim of this work was to assess the effect of pre-gestational diabetes and risk of adverse maternal, prenatal & neonatal outcomes in Alexandria-Egypt. From the results of this study we concluded that The patients with elevated HbA1C value of the increased risk of congenital fetal malformation and preeclampsia when the cut off value is > 6.9 , And risk of natal complications and respiratory distress when the cut off value is > 6.8 And affect time of delivery and abortion when the cut off value is > 7.0 . Diabetes plays an increasing role in the number of children born with congenital anomalies