Expert clinician-educators review the diagnosis of prediabetes and diabetes, including less common forms, such as maturity-onset diabetes of the young and latent autoimmune diabetes in adults, as well as the role of lifestyle interventions, appropriate indications and practical utilization of weight-loss medications. The risks and benefits of new insulin and noninsulin pharmacologic therapies are also presented. The role of diabetes medications, cholesterol-lowering agents, and blood pressure control to reduce cardiometabolic risk is also discussed.