The link between an adverse intrauterine environment and the development of disease later in life has been observed in offspring of pregnancies complicated by obesity and diabetes, but the molecular mechanisms underlying this phenomenon are unknown. In this review, we highlight recent publications exploring the role of gestational diabetes mellitus in the programming of disease in the offspring. We also review recent publications aiming to identify mechanisms responsible for the “programming effect” that results from exposure to diabetes in utero. Finally, we highlight research on the role of epigenetic regulation of gene expression in an animal model of uteroplacental insufficiency where the offspring develop diabetes as a model by which an exposure to the mother can alter epigenetic modifications that affect expression of key genes and ultimately lead to the development of diabetes in the offspring.