We describe successful generation of new NOD strains with targeted mutations in the murine ortholog of the human T1D candidate gene UBASH3A. We demonstrated that UBASH3A deficiency accelerated insulitis and T1D progression in both sexes and provided evidence to support that UBASH3A regulates autoimmune diabetes through its expression in T cells. The gene discussed is UBASH3A; the disease is type 1 diabetes mellitus.