This chapter describes antenatal care in diabetes in pregnancy. Diabetes is a common medical disorder occurring in pregnancy. It has become the modern epidemic and recently India has become capital of diabetes. Increasing incidence of diabetes in pregnancy reflects increasing prevalence of obesity and metabolic syndrome due to older maternal age, adoption of modern lifestyle, changing eating habits, and reduced physical activity. This chapter covers the etiological classification of diabetes mellitus, effect of pregnancy on diabetes, effect of diabetes on pregnancy, management, screening for gestational diabetes mellitus, diagnostic criteria for gestational diabetes mellitus, preconception counseling, antenatal care, insulin pen, and oral antidiabetic drugs. The management of GDM must involve a team approach consisting of obstetrician, diabetes physician, a diabetes educator, dietician, midwife, and pediatrician. Insulin pens are recommended to make the injections accurate, discreet, and painless with successful self-administration.