Five types of commercial bottle feeds for babies have been investigated against five other experimentally made by ourselves that were equivalent to a domestic preparation. We found that all biological index of protein quality were higher in our experimental lots, and the same happened with chemical index, with the exception of chemical score of the variety "Sole with potato". On the other hand it was proved that fat digestibility was good in any case, although the incidence on that index of both manufacturing processes was not clear. The results could be attributed once left out high sterilization influence, to two sets of factors that arise a two levels: a) Quality of initial protein source upon which operate subjective factors such as selection and cleanliness of original ingredients, and b) Manufacturing conditions.