Diabetes mellitus is a chronic illness that requires continuing medical care and ongoing patient self-management education and support to prevent acute complications and to reduce the long-term complications. Moderate-to-severe maternal hyperglycemia in pregnancy has unique diabetes-related risks to mother and her unborn baby. So, gestational diabetes mellitus (GDM) is a carbohydrate intolerance that has been diagnosed for the first time during pregnancy. Approximately, 7% of pregnancies are affected by GDM. Patients with GDM are at higher risk for excessive weight gain, preeclampsia, and cesarean sections. Infants born to mothers with GDM are at higher risk for macrosomia, birth trauma, and shoulder dystocia. After delivery, these infants have a higher risk of developing hypoglycemia, hypocalcemia, hyperbilirubinemia, respiratory distress syndrome, polycythemia and subsequent obesity, and type II diabetes. The management of GDM is very important, and its management remains a challenge for obstetricians and endocrinologists. Medical nutritional therapy (MNT) is the initial and most common therapy that suffices for GDM. Pharmacological therapy becomes necessary, and the treatment of choice is human insulin. Oral hypoglycemic agents have also reached the high tables in the management of GDM. Glyburide and metformin have been found to be safe, effective, and economical for the treatment of gestational diabetes.