Women with type 2 diabetes were less likely to have diabetes related complications than women with type 1. Women with type 1 diabetes had a high prepregnancy care and showed a worse glycemic control than women with type 2 both in the preconception period and during pregnancy. Obstetrical outcomes showed that preeclampsia and stillbirth rate is almost doubled in type 1 patients while perinatal deaths and SGA importantly increased in type 2 diabetes. In modern obstetrical care it is mandatory to maintain glucose levels as close to normal as possible particularly in diabetic population. HbA1C no higher than 6% before pregnancy and during the first trimester seems to decrease the risk of adverse obstetrical outcomes. Both the preconceptional counseling and glycemic profile optimization represent a fundamental step to improve pregnancy outcomes in women with preexisting diabetes. A systematic approach to family planning and the availability of preconception care for all diabetic women who desire pregnancy could be an essential step for diabetic management program.