Adiponectin, also referred to as Acrp30, AdipoQ, apM1, and GBP28, is a 276-amino acid protein specific for adipose tissue. This paper describes molecular mechanisms of adiponectin action, and clinical consequences of its various biochemical functions. Also, a common concept of the role of a low adiponectin level in the development of obesity, type 2 diabetes, insulin resistance, and dyslipidaemia is presented, and compared to other opinions that consider the paradoxical association between hypoadiponectinaemia and increased amount of fat tissue.