Now that prediction of type I diabetes mellitus has markedly improved, worldwide attempts to prevent the disease are under way (e.g., DPT-1, ENDIT, and TRIGR). Subjects are being recruited and families of children or parents with diabetes should be informed about the availability of such studies and given the option to participate. The creation of a network of study sites or cooperative groups will allow for the implementation of new protocols aimed at preventing the disease. The greatest barrier to the prevention of diabetes is the lack of proven effective interventional agents. The journey toward prevention of type I diabetes mellitus has only just begun.