The metabolic syndrome, a clustering of cardiovascular disease (CVD) risk factors, has been widely used in research and clinical practice. However, the American Diabetes Association and the European Association for the Study of Diabetes jointly issue a critical appraisal of the syndrome, questioning its precise definition, underlying pathogenesis, and value as a CVD risk marker. The review highlights several issues, including ambiguous criteria, lack of certainty about the syndrome's pathogenesis, and uncertainty regarding its utility as a CVD risk marker. The authors argue that the metabolic syndrome is not well-defined and characterized, and that its value as a CVD risk marker is uncertain. They also discuss the treatment of the metabolic syndrome and call for further research to improve our understanding of the syndrome. The review concludes that clinicians should evaluate and treat all CVD risk factors without regard to whether a patient meets the criteria for the metabolic syndrome diagnosis.The metabolic syndrome, a clustering of cardiovascular disease (CVD) risk factors, has been widely used in research and clinical practice. However, the American Diabetes Association and the European Association for the Study of Diabetes jointly issue a critical appraisal of the syndrome, questioning its precise definition, underlying pathogenesis, and value as a CVD risk marker. The review highlights several issues, including ambiguous criteria, lack of certainty about the syndrome's pathogenesis, and uncertainty regarding its utility as a CVD risk marker. The authors argue that the metabolic syndrome is not well-defined and characterized, and that its value as a CVD risk marker is uncertain. They also discuss the treatment of the metabolic syndrome and call for further research to improve our understanding of the syndrome. The review concludes that clinicians should evaluate and treat all CVD risk factors without regard to whether a patient meets the criteria for the metabolic syndrome diagnosis.