Phenylketonuria (PKU) and maple syrup urine disease (MSUD) are disorders of the amino acid metabolism. Treatment of PKU and MSUD, is based on the restriction of the involved amino acids. Diet must begin very early in life in order to prevent neurological sequelae. A wrong dietary produce central nervous system damage. The first clinical manifestations are unexplained failure to thrive, vomiting, feeding difficulties, lethargy, coma, acidosis and irritability. The most severe consequence is impaired mental development. The standard exchange foods list (EFL) used in outpatient clinics, is designed for developed countries, and contains foods that are not available in our countries. Therefore, we provide in this article a EFL, based on food that are frequently used in Central America, with data of existing food composition tables. This list is currently being used by the Costa Rica national Children's Hospital Metabolic Disease Unit.