Methods of measuring obesity are briefly reviewed. The more precise methods of measuring the body-fat mass are too complex and expensive for use in regular public health practice or individual screening. Anthropometry can, however, provide useful information. Two anthropometric indicators of obesity or overweight are recommended for classifying obesity. For adults, the body-mass index is reasonably easy to obtain and correlates well with mortality and morbidity risk. For children, "overweight" is indicated by a weight-for-height above the median NCHS value plus two standard deviations. Data compiled by the WHO Nutrition Unit, using these two indicators, are presented for a number of countries worldwide in Table 1 & Fig. 1.