A pilot prospective follow-up study of the role of the branched chain amino acids as additional therapy to the ketogenic diet was carried out in 17 children, aged between 2 and 7 years, with refractory epilepsy. All of these patients were on the ketogenic diet; none of them was seizure free, while only 13 had more or less benefited from the diet. The addition of branched chain amino acids induced a 100% seizure reduction in 3 patients, while a 50% to 90% reduction was noticed in 5. Moreover, in all of the patients, no reduction in ketosis was recorded despite the change in the fat-to-protein ratio from 4:1 to 2.5:1. Although our data are preliminary, we suggest that branched chain amino acids may increase the effectiveness of the ketogenic diet and the diet could be more easily tolerated by the patients because of the change in the ratio of fat to protein.