Gestational diabetes mellitus (GDM) affects approximately 4% of all pregnant women in the US and represents 90% of all cases of diabetes mellitus diagnosed during pregnancy. In addition to the adverse pregnancy outcomes associated with this complication, a history of GDM predisposes women to the future development of type 2 diabetes mellitus (T2DM). Incidence rates of GDM are increasing in the US. As a consequence, a growing number of women are now at increased risk for T2DM. Opportunities to diagnose and prevent T2DM in women with a history of GDM include early diagnosis by postpartum screening and implementation of diabetes prevention measures. In this Review, we discuss current guidelines for postpartum screening, how they might be implemented, and who should take responsibility for screening individuals at risk of T2DM. In addition, we describe measures to prevent the onset of T2DM in women with a history of GDM, focusing on lifestyle modifications, such as diet and breast-feeding.