Although metabolic syndrome is generally associated with type 2 diabetes mellitus, the present review emphasizes the possible presence of metabolic syndrome in type 1 diabetes and the impact of insulin resistance on micro- and macrovascular complications. Results of major intervention studies in type 1 diabetes have led to a generalized intensive insulin treatment, being an excessive weight gain one of the consequences. Since abdominal obesity and hyperglycemia are 2 components of the metabolic syndrome, an increase in the percentage of metabolic syndrome in patients with type 1 diabetes is not surprising, though its prevalence does not reach that reported for type 2 diabetes. For insulin sensitivity quantification in patients with type 1 diabetes the estimated glucose disposal rate (eGDR): it consists of calculating a score based on clinical factors of the patient, which shows an inverse relationship with the development of micro- and macrovascular complications. Moreover, insulin-resistance identification in type 1 diabetes may have therapeutic implications.