Gestational diabetes mellitus (GDM) is one of the most common complications of pregnancy.The aim of this study was to evaluate the prevalence, risk factors, and maternal and infant outcomes of women with GDM and to assess the awareness toward postpartum GDM.This is a descriptive cross–sectional study of 1050 women who attended and delivered at Maternity and Children Hospital, Dammam, Saudi Arabia,.The prevalence of GDM was 3.05%, and its only risk factor was history of GDM. GDM mothers were at increased risk of pregnancy–induced hypertension, preterm labor, intensive care unit admission, and delivery with caesarian section. Infants born to GDM mothers were at high risk of macrosomia, neonatal hypoglycemia, neonatal hypocalcaemia, and respiratory distress syndrome. Approximately half of GDM mothers had postpartum GDM. Thirty percent ofwomen had adequate level of awareness and the importance of postpartum follow–up.