Psychiatric problems of the child and the adolescent in Algeria are discussed in light of traditional psycho-social factors and in the modern world. The emphasis is on the frequency and severity of troubles of organic origin. Parallely, the impact of new aspects, coming from consequences of socio-cultural mutations, is understressed. This study underlines relationships between psychiatric aspects and socio-economical and cultural factors, and the role of the psychiatrist, with the heavy responsabilities he has to face in all areas if he wants to remain in his therapeutic role (Acta psychiat. belg., 1977, 77, 587-622).