The genetical types were classified according to the clinical findings and biochemical results in cases of 13 newborn/children suffering from various aminoacidopathies. The genetical types were: 3 neonatal and 4 infantile types were found out of 7 non-ketotic disease (MSUD) patient was infantile type with 9.1 per cent keto acid decarboxylase activity in leukocyte homogenate. Among the 3 histidinemic patients 1 was severe neonatal type and 2 cases were chronic types. The 2 treated tyrosinemic children proved to be type III. (chronic with rickets).