Fifty girls who were arrested in Boston on a charge of running away and their parents were studied via psychiatric interviews, rating schedules and psychotherapeutic data. There was an absence of psychosis and mental retarda tion in this group. A diversity of factors leading to running away episodes were elicited. Sexual factors were common. Family disturbances were usually found, reflecting in part the urban areas from which this group came. The girls showed a remarkable uniformity of behavior while on the run. Treatment of the whole family was often necessary for success in dealing with the runaway problem. The importance of intervention promptly is demonstrated by the associated self-destructive behavior of the girls, the frequency of severe family disturbances and the later histories of these youngsters.