Type 2 diabetes mellitus is an increasingly prevalent disorder associated with multiple metabolic derangements. Insulin resistance is the most prominent feature common in both type 2 diabetes and its associated metabolic abnormalities. Until 1995, the only therapeutic interventions available in the United States were the insulin secretagogues sulfonylureas and insulin. With the introduction of metformin in the United States in the mid-1990s and the subsequent advent of thiazolidinediones, an opportunity exists to address and directly reverse, at least in part, the defects in insulin action seen in individuals with type 2 diabetes. Evidence shows that insulin sensitizers not only have beneficial effects on glycemic control but also have multiple effects on lipid metabolism and atherosclerotic vascular processes that could prove to be beneficial. We discuss safety issues of these agents, their potential use in preventing onset and progression of diabetes, and their use in other related metabolic conditions such as polycystic ovary syndrome.