Serious juvenile delinquency is a problem which must be of major concern to any society. The question is, however, how to regard this phenomenon: as manifestations of psychiatric illness, needing psychiatric treatment; as behavior disorders, needing educational treatment and social support; or as extremes of normal behavior which should be dealt with by the ordinary penal system. Many authors have described severe personality disorders and/or behavior disorders among juvenile delinquents especially in those who have committed violent acts (see e.g., Alessi, McManus, Brickman, & Grapentine, 1984; Hartelius, 1965; Nielson, Young, & Latham, 1982; Russell, 1979; Shanok et al., 1983; Zenoff & Zients, 1979). In some cases evident psychotic disturbances are seen (Hartstone & Cocozza, 1983; Inamdar, Lewis, Siomopoulos, Shanok, & Lamela, 1982). A group of young delinquents, however, which may cause special difficulties is the group of criminals with borderline disorders, because these conditions are relatively recently described, consensus of the concept has not yet been obtained and the treatment is complicated. The sanctions used against the juveniles differ with the general attitude of society and also with the kind of available treatment facilities. Adolescents with personality and/or behavior disorders will often be subjected to educational and social treatment, the psychotics to psychiatric treatment. Again, there may be doubt as to the best possible sanctions against the borderline delinquents. The present paper deals with a sample of juvenile delinquents, nearly all of whom have committed very serious crimes. One purpose of the paper is to describe these delinquents’ background and psychosocial development. A second purpose is to discuss the concept of borderline disorders within this selected group of juveniles. Finally, the third purpose is to discuss the possibilities