Determination of cutoff points of waist circumference is of paramount importance for prevention, optimum management, and prognostication of obesity, the metabolic syndrome, type 2 diabetes mellitus, and coronary heart disease. Heterogeneity of composition of abdominal tissues, in particular adipose tissue and skeletal muscle, and their location-specific and changing relations with metabolic factors and cardiovascular risk factors in different ethnic groups do not allow a simple definition of abdominal obesity that could be applied uniformly. In particular, Asians appear to have higher morbidity at lower cutoff points for waist circumference than do white Caucasians. International health agencies that deal with obesity (World Health Organization, International Obesity Task Force) should take cognizance of these data and consider formulating new cutoff points for waist circumference to define abdominal obesity for Asian populations.