Although insulin resistance is usually associated with the development of type 2 diabetes, it can also be a feature of patients with type 1 diabetes. Insulin resistance has been documented in type 1 diabetes and may contribute to the high risk of cardiovascular disease in this population. To investigate the relationship of insulin resistance with metabolic and inflammatory parameters we divided 304 patients according to median estimated glucose disposal rate (eGDR = 9.72 mgkg(-1)min(-1)) into lower (n = 153) and higher (n = 151) insulin sensitivity groups. Patients with lower insulin sensitivity had higher levels of serum lipids (except for HDL cholesterol), duration of diabetes, daily insulin dose, white blood cell count, C-reactive protein, homocysteine and ferritin. Spearman correlation analysis showed significant associations between individual components of insulin resistance and various metabolic and inflammatory parameters. Multiple logistic regression models found significant association of age, sex, duration of diabetes, serum lipids, daily insulin dose, white blood cell count and ferritin with progression to insulin resistance. The presence of insulin resistance indicates a greater risk of micro- and macrovascular disease and health care professionals need to be alerted that this subset of individuals with type 1 diabetes will require stringent control of hypertension, glycemia and serum lipids.