We analyzed 97 children and young persons (< 20 years of age) with newly diagnosed diabetes for antibodies to islet cells (ICAs), glutamic acid decarboxylase (GADAbs), second-islet antigen (IA2Abs), and insulin (IAAs) in order to evaluate the prevalence of immune-mediated type 1 diabetes, as well as to recognize which autoantibody combination is better associated with the disease. A positive result for one or more diabetes-related antibodies evaluated was found in 92 children (94.8%): 41 females (95.3%) and 51 males (94.4%). With regard to single autoantibody testing, ICA levels were found to be positive in 84 patients (86.6%), GADAbs in 71 (73.2%), IA2Abs in 60 (61.8%), and IAAs in 51 (52.6%) patients. Combining the determination of at least two autoantibodies, ICAs and/or GADAbs were more frequently detectable than other antibody combinations, being positive in 89 patients (91.8%). Our data indicate that the vast majority of cases of type 1 diabetes in children may be considered as immune-mediated, that multiple autoantibody analysis improves identification of the disease, and that first-level screening is provided by the combined detection of ICAs and GADAbs.