Generally, most cases of diabetes mellitus (DM) are classified as either type 1 DM or type 2 DM based on their pathophysiolgic features. However, it is not always possible to classify this disease clearly according to current diagnostic criteria. Recently, the existence of non-typical diabetes has been found in patients with simultaneous features of both type 1 and type 2 DM. In these patients, obvious evidence of insulin resistance, positivity of islet autoantibody, and progressive beta cell loss are observed concurrently. Moreover, this non-typical diabetes that usually occurs among children and adolescents has been defined as 'double diabetes', and its worldwide incidence has been on the increase as of late. Thus, there has been heightened interest among researchers about this ambiguous condition.