Genetic, environmental, and metabolic risk factors are interrelated and contribute to the development of type 2 diabetes mellitus. A strong family history of diabetes mellitus, age, obesity, and physical inactivity identify those individuals at highest risk. Minority populations are also at higher risk, not only because of family history and genetics, but also because of adaptation to American environmental influences of poor dietary and exercise habits. Women with a history of gestational diabetes as well as their children are at greater risk for progressing to type 2 diabetes mellitus. Insulin resistance increases a person's risk for developing impaired glucose tolerance and type 2 diabetes. Individuals who have insulin resistance share many of the same risk factors as those with type 2 diabetes. These include hyperinsulinemia, atherogenic dyslipidemia, glucose intolerance, hypertension, prothrombic state, hyperuricemia, and polycystic ovary syndrome. Current interventions for the prevention and retardation of type 2 diabetes mellitus are those targeted towards modifying environmental risk factors such as reducing obesity and promoting physical activity. Awareness of risk factors for developing type 2 diabetes will promote screening, early detection, and treatment in high-risk populations with the goal of decreasing both microvascular and macrovascular complications.