The author shows the characteristics of death as perceived by human beings: it is related with a major break and a major loss, with the transformation of the body, with passivity, with doubt and certainty, with fantasy and the unthinkable, with the search for a meaning and culprits. Death withdraws from common time and society. Then the author introduces dying and develops these issues, illustrating them with several clinical vignettes, in the context of a severe illness among children and adolescents. He describes more precisely the characteristics of the adolescents. At last, he shows the necessity to take into account the consequences of the present context of wars and terrorisms on adolescents' and even on children's perception of death.