The purpose of this study was to compare the validity of obesity indices among the body mass index (BMI), waist circumference (WC), and body fat percentage (BF%), and to determine which is the most useful index to predict the risk of chronic diseases of elderly people. This study was conducted as a cross-sectional study at welfare centers in Seoul. The total number of subjects was 261 (68 men and 193 women) with age ${geq}60$ years. The distribution of obesity using 3 obesity indices in the subjects with hypertension, diabetes, or arthritis was BF%>WC>BMI in elderly men and WC>BF%>BMI in elderly women. In elderly women, odds ratios (ORs) for hypertension in BMI and WC quartiles were significantly increased in quartile 2 and 3 (p<0.05). The ORs for hypertension, hyperlipidemia, and arthritis in BF% quartiles were significantly increased in quartile 3 and 4 (p<0.05). The BF% was sensitive obesity index for predicting the occurrence of chronic disease in men, and the WC was sensitive index in women. Our results suggested maintaining BMI less than $23.5kg/m^2$, WC less than 82 cm, and BF less than 35% in order to prevent chronic diseases in elderly women.