Type 2 diabetes mellitus is a heterogeneous and multifactorial disorder accompanied by severe complications and a reduced life expectancy. Histopathologically, it is characterized by deposition of protein in the islets of Langerhans in the pancreas ('islet amyloid'). The 37 amino acids 'islet amyloid polypeptide' (IAPP) was discovered in 1986 as the building block of islet amyloid. The identification of IAPP caused an intensification of research on islet amyloid. In the past few years, particularly transgenic mouse technology has shown that islet amyloidosis is a consequence as well as an (additional) cause in the pathogenesis of type 2 diabetes. Islet amyloid has turned out to be a pathogenic factor, which is accompanied by death of beta-cells and reduction of the insulin producing capacity. This knowledge offers opportunities for the development of novel (preventive) therapy and thus for a better life expectancy of persons which develop type 2 diabetes.