Adiponectin, also known as Acrp30, AdipoQ, and GBP28, is an adipocyte-secreted protein that circulates in high concentrations in the serum and acts to increase insulin sensitivity. Adiponectin modulates a number of metabolic processes, including glucose regulation and fatty acid oxidation. The serum concentration of adiponectin decreases in obese patients, opposite to other adipocytokines. In recent studies, serum adiponectin level progressively decreased in patients according to the severity of obesity, insulin resistance, diabetes mellitus and cardiovascular diseases. Low serum adiponectin level may be a predictive factor for type 2 diabetes mellitus (T2DM) and other cardiovascular diseases.