Although great progress has been made in our understanding of the molecular bases of mitochondrial disorders due to defects in the respiratory chain, little exists in the way of rational therapy. Possible therapeutic approaches include: palliative therapy; removal of noxious metabolites; administration of artificial electron acceptors, metabolites, and free radical scavengers; genetic counseling; and gene therapy. There has been progress with each of these approaches, although much work remains to be done. Finally, a novel approach to treating a specific mitochondrial disorder, MELAS, is presented.