Universal consensus on the diagnosis methods and thresholds has long been lacking. The recently published Hyperglycemia and Adverse Pregnancy Outcome (HAPO) study has been used to confirm the link between hyperglycemia and materno-fetal complications. Consequently, in France, the Société francophone du diabète (SFD) and the Collège national des gynécologues et obstétriciens français (CNGOF) proposed an expert consensus on gestational diabetes mellitus for clinical practice. Fasting blood glucose should be measured at the first visit during early pregnancy for women with risk factors to identify the women with pregestational diabetes. It is proposed a selective screening on risk factors rather than universal screening. Specific treatment of gestational diabetes reduced materno-fetal complications compared to the absence of therapy. Women with a history of gestational diabetes mellitus are characterized by a high risk of type 2 diabetes mellitus.