Diabetes in pregnancy may be gestational (90%) or pregestational (10%) when it antedates pregnancy. Pregnancy is a diabetogenic state due to impaired insulin sensitivity. Pregnancy worsens diabetes, while poorly controlled diabetes results in fetal, neonatal and maternal complications. As gestational diabetes is asymptomatic, glucose challenge test is done for screening while glucose tolerance test is used in diagnosis. Insulin therapy is required in 15 percent of gestational diabetics and in all pregestational diabetics during pregnancy. Diet and exercise also play a significant role in controlling blood sugar. Preconception counseling improves the outcome of pregnancy in pregestational diabetic women. Gestational diabetes recurs in subsequent pregnancies and increases the risk of type 2 diabetes in later life. Diabetes mellitus is a common medical disorder encountered in pregnancy. Maternal and fetal prognosis today for women with well controlled pregestational diabetes is also satisfactory. Gestational diabetes generally occurs in the latter half of pregnancy. Maternal complications are 2 to 4 folds higher in a diabetic pregnancy. Two methods of screening that are in practice today are: 1. Universal screening and 2. Selective screening. All pregnant women are screened in the universal screening protocol while selective screening is done only in the presence of risk factors for gestational diabetes.