Interleukin-36 (IL-36) is a pro-inflammatory cytokine which plays an important role in innate and adaptive immunity. IL-36 activates MAPK and NF-kB pathways and is produced by many different cells. This cytokine is a family member of interleukin-1 (IL-1) and plays an important role in the pathophysiology of several diseases. Here we summarise and review the new aspects of this important pro-inflammatory cytokine.