Diabetes is one of the most common medical conditions to complicate pregnancy. Gestational diabetes (diabetes with onset or first recognition in pregnancy) may complicate between 2 and 20% of pregnancies depending on the criteria used. Type 1 or Type 2 diabetes complicates over 1 in 300 pregnancies, and both have major implications for mother and child. The management of diabetes during pregnancy has seen a number of major innovations in recent years. Insulin analogues have been introduced, and technical innovations include improvements in insulin pumps and the development of continuous glucose monitoring devices. The evidence base for the management of gestational diabetes has improved markedly, and the investigations based around the Hyperglycaemia and Adverse Pregnancy Outcomes (HAPO) study promise to revolutionise our understanding of the risks of adverse outcomes in pregnancy. The Australian Carbohydrate Intolerance Study (ACHOIS) has demonstrated that identification and glycaemic management of gestational diabetes leads to reduction in birth weight, macrosomia and adverse pregnancy outcomes. Finally, recent randomised control trials have explored use of oral hypoglycaemics (metformin, glibenclamide) in pregnancy. Part of the Oxford Diabetes Library series, 'Diabetes in Pregnancy' summarizes the key aspects of the medical management of diabetes during pregnancy with an emphasis on clinical management. The volume is designed for all members of the multidisciplinary team and will act as a practical introduction particularly for obstetricians and endocrinologists in training.