Insulin resistance is considered a core component in the pathophysiology of the metabolic syndrome. Some clinicians measure serum insulin concentrations in the mistaken belief that they can be used to diagnose insulin resistance. Serum insulin levels are poor measures of insulin resistance. Furthermore, there is no clinical benefit in measuring insulin resistance in clinical practice. Measurements of fasting serum insulin levels should be reserved for large population-based epidemiological studies, where they can provide valuable data on the relationship of insulin sensitivity to risk factors for diabetes and cardiovascular disease. Clinicians should shift from identifying "insulin resistance" to identifying risk factors, such as fasting glucose and lipid levels, hypertension and central obesity. These proven risk factors converge within the metabolic syndrome. Individuals "at risk" of diabetes and atherosclerotic cardiac disease can be identified simply and inexpensively, using classic clinical techniques, such as history-taking, physical examination, and very basic investigations.