Type 1 diabetes is caused by the autoimmune destruction of insulin-producing cells with consequent hyperglycemia and serious chronic complications. Both innate and adaptive immune responses participate in disease pathogenesis. Studies in animal models and in man have shown that NK cells are involved both in disease progression and in disease protection, thus suggesting that NK cells can represent a potential therapeutic target in type 1 diabetes, once the contribution of these cells to islet autoimmunity has been fully elucidated.