Abstract: A phenylalanine-free nutrient base for infants and small children, sad also a process for the production thereof, are provided. This nutrient base, in addition to an amino acid mixture which has all L-amino acids necessary for the nutrition of the child, except for phenylalanine, also contains fats sad/or carbohydrates sad also, optionally, minerals and/or trace elements. This nutrient base is produced by spray-drying of an aqueous formulation containing these components. During this, at least the amino acids lysine and cystine are at least in part mixed into the spray-dried product obtained after the spray-drying. Owing to the fact that these amino acids are not spray-dried with the others, the end product obtained is free of undesired by-products that form during spray-drying.