Interleukin 24 (IL-24) is a pleiotropic immune cytokine belonging to the IL-10 family, which includes several members (IL-19, IL-20, IL-22, IL-24, IL-26). IL-24 is secreted by several myeloid and lymphoid cells and also by tumor cells, and acts on immune cells as well as on non-hematopoietic tissues. It is specific for two different heterodimeric receptors, IL-20R1/IL-20R2 and IL-22R1/IL-20R2, and can control cell differentiation and apoptosis, as well as tumor growth, acting on angiogenesis and cell proliferation. IL-24 plays an important role in tumor immune surveillance, but also in skin related diseases and wound healing.