The increased cardiovascular risk in type 1 diabetes may be related, at least in part, to insulin resistance. The aim of this study was to assess the relationships between insulin sensitivity, abdominal fat, androgens, lipids, and blood pressure in 10 premenopausal women with type 1 diabetes (mean +/- SD, hemoglobin A1c 8.1 +/- 1.0%) and 10 nondiabetic body mass index-matched controls. Insulin sensitivity (glucose infusion rate during euglycemic-hyperinsulinemic clamp) was significantly less in the type 1 diabetes group than in controls (49.3 +/- 14.8 vs. 73.2 +/- 21.6 micromol/min x kg fat free mass, respectively, P = 0.01). The two groups were similar with respect to lipids, androgens, energy expenditure, physical activity, blood pressure, and abdominal adiposity (intra-abdominal fat by four-slice computed tomography and central abdominal fat by dual-energy x-ray absorptiometry). There were no relationships between glucose infusion rate, abdominal adiposity, and androgen levels in subjects with type 1 diabetes, in contrast to controls. Our results demonstrate greater insulin resistance in a group of premenopausal women with type 1 diabetes compared with nondiabetic controls, unrelated to abdominal adiposity, lipids, or androgens.