Abdominal composition was quantified from computed tomography (CT) scans of 96 clinically normal men and women aged 20-83 y. Measurements were taken of total and intraabdominal areas and of muscle, bone, and subcutaneous and intraabdominal adipose-tissue areas from each of six 8-mm-thick transverse slices from CT images of abdomen and pelvis. Men had a significantly greater percentage of intraabdominal adipose tissue than women and the percentage increased with age in each sex. Percentages of total abdominal area that were adipose tissue were significantly negatively correlated with percentages of muscle and bone in each sex. Ratios of total areas of abdominal slices to total areas of pelvic slices (analogous to waist:hip ratios) had significant positive correlations with the absolute and relative areas of intraabdominal and subcutaneous adipose tissue for the abdomen in women but not in men. These ratios also had significant negative correlations with absolute and relative areas of muscle and bone in women.