This paper updates available evidence on the costs to society associated with noncompletion of school by substantial numbers of American youth. The only comparable treatment of this topic was published in 1972 by Henry M. Levin. The findings of this earlier study are recast to account for current earnings projections and price levels, and for current patterns of dropping out both nationally and in urban centers. The analysis includes women in the labor force. Several important qualifications regarding the cost perspectives chosen are discussed, and their possibilities for cost assessments are explored. A conclusion of this analysis is that a conservative appraisal of costs of dropping out yields estimates far in excess of the resources devoted to dropout prevention. A discussion of why this imbalance persists is presented, focusing on inadequate action by schools and communities and lack of consensus on the issue. Four tables and 14 endnotes are appended. (CJH)