Measurements of regional body fat distribution as determined by waist-to-hip ratio and visceral-to-subcutaneous adipose tissue ratio were compared in 63 obese women. Subjects were divided into three CT-evaluated tertiles on the basis of visceral-to-subcutaneous adipose tissue ratio (group I, 0.05-0.231; group II, 0.232-0.344; group III, 0.345-0.781). The three groups showed no appreciable differences in body weight, body mass index or total abdominal adipose tissue. Waist-to-hip ratio values were significantly lower in group I than in groups II and III. There was no statistically significant difference between groups II and III. Visceral abdominal adipose tissue was significantly and progressively higher in the three groups. Subcutaneous abdominal adipose tissue was significantly lower in group III than in group I. All metabolic variables and systolic and diastolic blood pressure were higher when visceral-to-subcutaneous adipose tissue ratio cut-off values were increased. Waist-to-hip ratio was significantly correlated with total adipose tissue, body mass index, visceral abdominal adipose tissue and subcutaneous abdominal adipose tissue. Visceral-to-subcutaneous adipose tissue ratio was correlated with visceral abdominal adipose tissue (r = 0.84, P < 0.01) and subcutaneous abdominal adipose tissue (r = -0.28, P < 0.05). There was no correlation between visceral-to-subcutaneous adipose tissue ratio and body mass index or total abdominal adipose tissue. Visceral-to-subcutaneous adipose correlated more closely with metabolic variables than did waist-to-hip ratio. Partial correlations between waist-to-hip ratio and visceral-to-subcutaneous adipose tissue ratio and metabolic variables, adjusted for body mass index, showed statistically significant relationships for visceral-to-subcutaneous adipose tissue ratio, but not for waist-to-hip ratio. Visceral-to-subcutaneous adipose tissue ratio correlated with waist-to-hip ratio in the study population as a whole, but only in group I did the correlation between visceral-to-subcutaneous adipose tissue ratio and waist-to-hip ratio prove statistically significant. The present study demonstrates that visceral-to-subcutaneous adipose tissue ratio is a better index of body fat distribution than waist-to-hip ratio.