Background: The presence of insulin resistance (IR) and metabolic syndrome (MS) in patients with type 1 diabetes (T1D) has been called "double diabetes". This entity increases the risk for development of micro and macrovascular complications and cardiovascular mortality. The gold standard for IR quantification is the hyperinsulinemic euglycemic clamp (HEC) but it is invasive, time-consuming and not available in the majority of the clinical settings. Because of this, some formulas for IR quantification have been proposed. We aimed to compare the utility of those methods for MS detection in patients with T1D. Methods: We conducted a cross-sectional study in 112 patients with T1D and determined the presence of MS using the Joint Statement Criteria. We calculated the estimated glucose disposal rate (eGDR), estimated insulin sensitivity index (eIS), natural logarithm of glucose disposal rate (lnGDR), triglyceride/high-density lipoprotein cholesterol ratio (TG/HDL-c), visceral adipose index (VAI) and waist-to-height ratio (WHtR), and compared among patients with and without MS using Student t-test or Mann-Whitney U test. Receiver Operating Characteristics curves for the different indexes were used to identify the best cutoff points for MS detection. Results: Thirty three percent of the patients were considered to have MS. The patients with MS had lower eGDR (5.