This book aims to educate the readers with detailed knowledge regarding gestational diabetes. Gestational diabetes mellitus is described as hyperglycemia with onset or first recognition during pregnancy. The occurrence of gestational diabetes is rapidly increasing and this pathological condition has a strong association with adverse pregnancy results. Since gestational diabetes can have chronic pathological consequences for both mother and child, it is important that it is instantly recognized and suitably managed. Treatment of this kind of diabetes is aimed to maintain euglycemia and it should include routine glucose monitoring, dietary modifications, changes in life style, appropriate physical activity and when required, pharmacotherapy. Appropriate glycemic control throughout the pregnancy can significantly reduce the existence of specific adverse perinatal and maternal consequences. In a long term aspect, for avoiding diabetes to develop further in life, as well to prevent related complications, a necessary education on lifestyle modifications should start in pregnancy and should continue postpartum.