Type 1 diabetes mellitus (T1DM) can be found amongst the first accounts of any diseases noted. A diabetes diagnosis in these ancient times was most certainly a terminal one. This disease is caused by autoimmune responses, and that patients develop autoimmunity well before the clinical onset of the disease. Type 1 diabetes mellitus is unique among other autoimmune diseases for two simple reasons: if left untreated, it is almost immediately deadly, but on the flip side of the coin, we have a means to treat the disease without having to modulate the immune response by using insulin. This chapter covers the staging of type 1 diabetes mellitus, defining a “cure” for type 1 diabetes mellitus, and treatment and cure pipeline.