Mitochondrial morphology is tightly regulated by fusion and fission manner that are essential for maintaining physiological function of cells. Besides controlling the morphology of mitochondria, there is accumulating evidence that fusion and fission proteins play an active role in the control of cell movement, migration, and invasion. In our study, we found the upregulation of mitochondrial fusion protein and the elongated mitochondrial morphology in both migration of the immature dendritic cells (imDCs) and epithelial-mesenchymal transition (EMT) of retinal pigment epithelial cells. Specially, the mitochondrial fusion proteins, Mfn2 and OPA1, but not Mfn1, were transcriptionally increased during differentiation of bone marrow progenitors to imDCs. Knockdown of Mfn2 or OPA1 by siRNA significantly reduced CCR7 expression and CCL19-mediated migration in imDCs. During TGF--mediated EMT of retinal pigment epithelial cells, the mitochondrial fission protein OPA3 was transcriptionally downregulated. Knockdown of OPA3 dramatically increased stress fiber levels, cell length, cell migration and mitochondrial elongation. These results collectively substantiate the involvement of mitochondrial dynamics in cells migration.