Mitochondrial fission is the process by which mitochondria divide or segregate into two separate mitochondrial organelles. Mitochondrial fission is counteracted by mitochondrial fusion, where two mitochondria fuse together to form a larger one.[1] Fusion can result in elongated mitochondrial networks. In healthy cells, mitochondrial fission and fusion are balanced, and disruptions to these processes are linked to various diseases. Mitochondrial fission is coordinated with the mitochondrial DNA replication process.[2] Some of the proteins involved in mitochondrial fission have been identified, and mutations in some of these proteins are associated with mitochondrial diseases.[3] Mitochondrial fission plays a role in the cellular stress response and in apoptosis (programmed cell death).[4]