Type 2 diabetes mellitus has been catalogued as one of the many new epidemics of the twenty-first century. It is a multifactorial disease whose prevention constitutes an important objective for the primary level of medical attention. It was the aim of this review to explain the anatomophysiological alterations of type 2 diabetes mellitus. A bibliographical review of 21 sources was carried out. Type 2 diabetes mellitus is classified fundamentally by the presence of resistance to insulin or by a secretory defect thereof. Insulin resistance, metabolic syndrome and atherosclerosis are implicated in its pathogenesis and complications. Its clinical features and the values of glycaemia, be they fasting or postprandial, are indispensable for a diagnosis. A diabetological education that includes an adequate lifestyle will prevent complications and better the quality of life of these patients.
