Analyses of data obtained from 790 questionnaires collected from a sample of public high school seniors in a relatively low income, sparsely settled county in northern New York State in May, 1962, revealed some of the effects of 2 family systems--the immediate family and the extended family--on the migration planning of high school seniors. Hypotheses were formulated and tested with regard to the family functions of social-psychological support, economic support, and communication with relatives in other communities. When family members or relatives performed these functions, planning by youth to migrate was significantly more likely than when no family member performed these functions. Migration planning was also more likely when both family systems, rather than one, performed the functions. Little confirmation was given to the proposition that the immediate family was more important than other relatives in effecting plans to migrate. It was emphasized that while attachment to the immediate family was a barrier to migration, family support could overcome its effects. (SW)