In type 1 diabetes, a failure in the regulation of either innate or acquired immunity may be the cause of autoimmune response. A cell population that may have a regulatory role of the immune response are the Natural Killer T (NKT) cells, which are a population expressing T lymphocyte antigen receptor (TCR), and are a common marker for NK cells. A distinctive characteristic in NKT cells is their capacity to produce large amounts of immune-modulating cytokines. A decrease in the number and/or functional incapability of NKT cells is associated with progression of type 1 diabetes and with other self-immune diseases. However, the relevance of such findings is not completely understood. Limitations of the current studies include the existing methods to measure NKT activation and the lack of assessment of the expression of genes affected by NKT action. Nevertheless, the study of NKT cells may be a new clinical approach to detect individuals at risk for having type 1 diabetes. Additional studies are needed to evaluate the clinical value of this new predictive tool.