The king penguin Aptenodytes patagonicus is a highly colonial seabird breeding in large and dense colonies on the seashore of subantarctic islands. The ability to recognise mates, parents or chicks is particularly important in seabird colonies, where nest-sites are densely packed. To be fed, a king penguin chick must identify the call of its parents. To study the individual recognition and the coding and decoding features in the call, we played-back to the chicks different experimental signals. All responses obtained were compared with the response obtained by the parent's call. Firstly, we played back experimental signals made from artificially modified recordings of natural signals. Different features of the signals were modified independently of each other in order to determine their importance. Finally, we investigated the recognition process using a series of progressively more complex synthetic signals calculated accordingly to the importance of the parameters that we wanted to investigate.