Within the last couple of years much knowledge has been gained in understanding the immune interactions in endocrine diseases including endocrine malignancies and autoimmune diseases. The major players within the innate immune system represent NK cells. This review describes that these cells directly lyse tumor cells and promote the activity of other cells of the immune system, including dendritic cells (DCs), macrophages, Th1 cells, and cytotoxic T-lymphocytes (CTLs). NK cells may also be involved in the initiation of autoimmunity as they may accumulate in target organs of certain autoimmune diseases. On the other hand, there are cells of the adaptive immune system including antigen-presenting DCs and T cells with helper and effector function, which are responsible for a directed immune response. Within this review, we present an overview on the role of all these cell populations in endocrine disease and the potential use of such cells for immunotherapy in different endocrine diseases and refer to experimental settings as well as clinical studies.