We present the clinical and laboratory effects of dichloroacetate (DCA) in three children with mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes (MELAS) who had not responded to other medications. Administration of DCA lowered the elevated levels of lactate and pyruvate in the serum and CSF. DCA ameliorated abdominal pain, headache, and strokelike episodes, and improved cognitive function and fatigability in the three patients during the study period. Some transient liver dysfunction, hypocalcemia, and peripheral neuropathy were observed. The use of DCA in MELAS merits further study.