Accumulation of visceral adipose tissue is associated with meta- bolic complications such as noninsulin-dependent diabetes mellitus. The aim of this study was to evaluate the effect of abdominal adipose tissue on insulin sensitivity in subjects with noninsulin-dependent diabetes mellitus (NIDDM). Areas of abdominal fat were calculated from axial magnetic resonance images obtained at the level of the umbilicus in 21 men with NIDDM (age, 45.6 6 8.3 (6SD) yr; body mass index, 29.3 6 4.5 kg/m22; total body fat (skinfold thickness), 26.8 6 5.4%; waist to hip ratio, 0.97 6 0.07; duration of diabetes, 59 6 47 months; hemoglobin A1c, 8.1 6 1.5%). Insulin sensitivity was evalu- ated by an insulin tolerance test. The areas of deep abdominal fat and sc abdominal fat were, respectively, 135.3 6 55.1 and 211.8 6 99.1 cm2. The blood glucose disappearance rate was 2.11 6 0.87%/min and was negatively related to deep abdominal fat (r 5 0.72; P 5 0.0025). In contrast, areas of sc abdominal fat, total body fat, body mass index, and waist to hip ratio were not related to the blood glucose disap- pearance rate. Plasma triglyceride concentrations averaged 1.8 6 0.8 mmol/L and were positively related to deep abdominal fat (r 5 0.69; P 5 0.0018). We conclude that insulin sensitivity is strongly related to visceral adipose tissue accumulation in NIDDM. (J Clin Endocrinol Metab 83: 1306 -1311, 1998)