Obesity is associated with an increasedrisk of developing insulin resistance and type 2 diabetes. In obese individuals, adipose tissuereleasesincreased amounts of non-esterified fatty acids, glycerol, hormone, pro-inflammatory cytokines and other factors that are involved in the development of insulin resistance. When insulin resistance is accompanied by dysfunction of pancreatic islet β-cell — the cell that releaseinsulin — failure to control blood glucose levels results. Abnormalities in β-cell function are therefore critical in defining the risk and development of type 2 diabetes. This knowledge is fostering exploration of the molecular and genetic basis of the disease and new approaches to its treatment and prevention.