Although gestational diabetes may have serious consequences for both mother and fetus, it is usually symptomless. The diagnosis can be missed unless all pregnant women are screened to determine those who need a full oral glucose tolerance test. When gestational diabetes is diagnosed, it is essential to (1) achieve euglycemia with diet and, if needed, insulin and (2) monitor for potential complications. Glucose tolerance must be reevaluated in the post-partum period and periodically thereafter to detect continuing intolerance or diabetes.