The polycystic ovary syndrome (PCOS) and hyperandrogenism are some of the most common endocrine disorders in women of fertile age. Insulin resistance is present in a significant proportion of hyperandrogenic patients, yet also, impaired ß-cell function, even in absence of clinically evident glucose intolerance, is a frequent finding, especially in patients with familial history of type 2 diabetes mellitus. Therefore, it is not surprising that hyperandrogenism, PCOS, and disorders of carbohydrate metabolism are associated frequently. This association was first reported 75 years ago and, although the mechanisms responsible are not precisely understood, insulin resistance plays an important role in the development of both disorders. PCOS patients develop type 2 diabetes mellitus more frequently than non-hyperandrogenic women and, conversely, women with type 2 diabetes have a greater risk of having PCOS compared with the normal population. Although type 1 diabetes mellitus is a disease characterized by complete abolition of endogenous insulin secretion, a certain degree of hyperinsulinism may exist, resulting from the relatively excessive insulin doses needed to maintain a strict metabolic control. This exogenous hyperinsulinism may increase ovarian androgen secretion, and it has been reported that there is an increased prevalence of hyperandrogenic disorders in type 1 diabetic women. Considering that insulin resistance, hyperinsulinemia and androgen excess may collaborate in increasing the risk for CVD in these women, the identification of hyperandrogenic symptoms in diabetic women, and the identification of disorders of glucose tolerance in hyperandrogenic patients, may have important consequences for the correct management of these women.