OBJECTIVES: To determine the proportion of a representative population sample of adults in South Australia who have a body mass index (a measure of overall obesity) classified as normal or underweight, but who also have a waist circumference or waist hip ratio (measures of central obesity) that indicates obesity. METHODS: A representative population sample of adults aged 18 years and over living in the north west region of Adelaide (n = 2523) were recruited to the study. Clinical measures of height, weight, waist and hip circumference were obtained and used to determine body mass index, waist hip ratio and waist circumference. RESULTS: Among women with a normal body mass index, 19.0% had a high waist circumference ( 80 cm) and 8.5% had a high waist hip ratio (> 0.85). Among males with a normal body mass index, 3.4% had a high waist circumference ( 95 cm) and 0.1% had a high waist hip ratio (>1.0). CONCLUSIONS: Body mass index, waist hip ratio and waist circumference all have a role in the identification of those who are obese or overweight. ; Tiffany Gill, Catherine Chittleborough, Anne Taylor, Richard Ruffin, David Wilson and Patrick Phillips ; © Birkhäuser