Background: Body mass index (BMI; in kg/m(2)) is considered a poor indicator of overall and abdominal obesity in the elderly. Objectives: Our goal was to determine which simple anthropometric measurements [BMI, waist-to-hip ratio (WHR), waist circumference (WC), percentage body fat (%BF), or fat mass (FM)] are most closely associated with metabolic risk factors and insulin resistance in elderly men. Design: This was a cross-sectional study of 2924 men aged 60-79 y with no history of coronary heart disease, stroke, or diabetes who were drawn from general practices in 24 British towns. Results: BMI and WC were the measures most strongly associated with the metabolic syndrome ( 3 of the following: hypertension, low HDL cholesterol, high triacylglycerols, or high blood glucose) and insulin resistance. For a 1-SD increase in BMI, WC, WHR, %BF, and FM, the odds ratios (95% CIs) of having the metabolic syndrome after adjustment for age, socioeconomic status, smoking status, and physical activity were as follows: BMI, 1.61 (1.44,1.79); WC, 1.65 (1.48, 1.81); WHR, 1.49 (1.34, 1.66); %BF, 1.41 (1.25, 1.59); and FM, 1.53 (1.38, 1.70). For insulin resistance, the odds ratios (95 % CIs) were as follows: 2.48 (2.22, 2.77), 2.46 (2.19, 2.65), 1.75 (1.59, 1.93), 1.79 (1.60, 2.00), and 2.10 (1.88, 2.34), respectively. In normal-weight (BMI < 25) and overweight (BMI 25-29.9) men, the presence of the metabolic syndrome and insulin resistance increased with increasing WC; this did not occur in obese men. Conclusions: BMI and WC are the simple measures of adiposity most strongly associated with metabolic abnormalities in elderly men. Our findings suggest that WC can be used as a complementary measurement to identify health risks in normal-weight and overweight elderly persons.