We report on a young girl with Alpers-Huttenlocher syndrome, as confirmed by mitochondrial polymerase gamma sequencing, who was treated with the classic (4 parts fat:1 part each of carbohydrate and protein) ketogenic diet after she presented with epilepsia partialis continua. She improved clinically, and her electroencephalogram improved dramatically. This is the first detailed report on the efficacy of the ketogenic diet in treating the epileptic encephalopathy of Alpers-Huttenlocher syndrome. We present a literature review of the utility of a ketogenic diet in mitochondrial disorders, and speculations as to why the diet may be helpful in Alpers-Huttenlocher syndrome.