Successful therapy in cow's milk protein allergy rests on completely eliminating cow's milk proteins from the child's diet: it is thus necessary to provide a replacement food. This prospective study investigated tolerance of donkey's milk in a population of 46 selected children with cow's milk protein allergy, for whom it was not possible to use any cow's milk substitute. Thirty-eight children (82.6%) liked and tolerated donkey's milk at the challenge and for the entire duration of follow-up. Catch-up growth was observed in all subjects with growth deficit during cow's milk proteins challenge. The degree of cross-reactivity of immunoglobulin E (IgE) with donkey's milk proteins was very weak and aspecific. Donkey's milk was found to be a valid alternative to both IgE-mediated and non-IgE-mediated cow's milk proteins allergy, including in terms of palatability and weight-height gain.