The distribution of mitochondria to daughter cells during cell division is an essential feature of cell proliferation. Until recently, it was commonly believed that inheritance of mitochondria and other organelles was a passive process, a consequence of their random diffusion throughout the cytoplasm. A growing recognition of the reticular morphology of mitochondria in many living cells, the association of mitochondria with the cytoskeleton, and the coordinated movements of mitochondria during cellular division and differentiation has illuminated the necessity for a cellular machinery that mediates mitochondrial behavior. Characterization of the underlying molecular components of this machinery is providing insight into mechanisms regulating mitochondrial morphology and distribution.