The incidence of type 1 diabetes is increasing worldwide and the disease is an onerous burden both to the individual and to society. There are thus important reasons to screen for the disease before it becomes manifest: (1) to improve understanding of the natural history of the prediabetic period; (2) to gain further insights into the immunopathogenesis of the disease; (3) to identify individuals for prevention trials; (4) to make an earlier diagnosis in order to reduce morbidity and mortality. Great strides have been made, yet there is still a great deal to be learned. Opponents of screening argue that screening tests for the disease have a low positive predictive value and that predicting the disease without a primary prevention capability raises ethical considerations because of induced stress, lifestyle changes, cost and potential effects on insurability. The greatest single barrier against large-scale population screening and prevention of the disease remains the lack of an effective intervention. However, screening in the context of well-designed research studies must continue – ultimately the benefit to the individual and to society will be immense.