The importance of identifying children who are at risk of developing the metabolic syndrome cannot be underestimated. The syndrome is a cluster of risk factors for cardiovascular and type 2 diabetes, including abdominal obesity, dyslipidaemia, glucose intolerance and hypertension. The modern ‘obesogenic’ environment is one of a number of factors that are driving an increase in these risk factors in children and adolescents. The lack of a unified definition to assess risk or outcomes in children and adolescents prompted the International Diabetes Federation to develop a new, simple definition with the aim of providing a clinically accessible diagnostic tool to identify the metabolic syndrome in young people worldwide.