An overview describes people's basic needs--biological, workplace, familial, social, and spontaneous (physical, intellectual, and emotional). It is deemed necessary for both family and school to enter into meeting those needs for youth and directing youths' own efforts at fulfilling them through meaningful leisure and nonleisure pursuits. Juvenile delinquency and its development over 10 years in Hungary (1965-74) are examined to discover the kinds of infractions juveniles were committing and when those infractions most frequently occurred. The familial, school, and leisure circumstances of youths are studied with data from 303 juvenile delinquents and 120 control subjects nondelinquent youths in training at industrial apprenticeship centers). This analysis looks at these youths' social environments, school achievements, and the kinds of leisure activities they pursued both within the home and outside, and the kinds of infractions that were committed by the delinquent group. Correlations are then drawn and tabulated between the characteristics of these subjects and their leisure activities, with attention to parents' income, whether or not the child had siblings, the marital status of the parents, and whether or not the children were from urban or rural settings. Finally, attention is given to the influence of Hungary's state, social, and school institutions on youths' choices for leisure activities, with emphasis on the responsibility these institutions must take in providing youths with useful and meaningful leisure alternatives. Conclusions center on support for the hypothesis that prevention of criminality can be brought about through careful structuring and direction of leisure time activities. Extensive tables are provided. --in French.