Recent estimates indicate that two billion people are overweight or obese and hence are at increased risk of cardiovascular disease and its comorbidities. However, this may be an underestimate of the true extent of the problem, as the current method used to define overweight may lack sensitivity, particularly in some ethnic groups where there may be an underestimate of risk. Measures of central obesity may be more strongly associated with cardiovascular risk, but there has been no systematic attempt to compare the strength and nature of the associations between different measures of overweight with cardiovascular risk across ethnic groups. Data from the Obesity in Asia Collaboration, comprising 21 cross-sectional studies in the Asia-Pacific region with information on more than 263,000 individuals, indicate that measures of central obesity, in particular, waist circumference (WC), are better discriminators of prevalent diabetes and hypertension in Asians and Caucasians, and are more strongly associated with prevalent diabetes (but not hypertension), compared with body mass index (BMI). For any given level of BMI, WC or waist:hip ratio, the absolute risk of diabetes or hypertension tended to be higher among Asians compared with Caucasians, supporting the use of lower anthropometric cut-points to indicate overweight among Asians.