Fifty girls between the ages of 12 and 16 years who were charged in the Boston Juvenile Court as being runaways were, with their parents, studied via psychiatric interviews, rating schedules, and psychotherapeutic data. For comparisons of some aspects, control data were collected from well-adjusted high school girls of the same age. Scrutiny of the runaway girls' attitudes, feelings, and behavioral characteristics via the clinical rating scale revealed the runaways to be more aggressive, angry, impulsive, unstable, easily annoyed, and depressed, some to the point of suicidal preoccupation. Runaways more usually lied, stole, usually from mother, and were truant. Permissiveness and punitiveness were evident on the part of the runaways' parents. Adolescents assumed that separation from their parents would give them a more autonomous social life and the development of more clearly defined sexual roles. Conflicts of the oedipal type provoked marked anxiety. The data suggested that the runaway girl looks to her peer group for help and support when she runs away and chooses a nonpunitive environment in which experimentation with sexual activity and drugs is tolerated. Running away, while impulsive, was not as threatening to the youngsters as the threat of danger at home. Running away tended to be associated with the onset of puberty and early adolescence, overtly incestuous incidents between the girl and her father or father substitute, and promiscuous involvement with older boys. Brief separations via foster home care or institutional placement are helpful and provide evidences as to whether the child should be returned to the home. Treatment measures must include the whole family. Prompt intervention is necessitated by the associated self-destructive behavior of the girls and the frequency of severe family disturbances. Three case studies, tables, and 10 references are provided.