The study estimated that the typical “high-risk” youth with six or more police contacts, who collectively committed approximately 50 percent of all crimes, imposed between $4.2 and $7.2 million in costs. Discounted to current value at age 14, costs totaled $3.2-$5.8 million. The bulk of these costs were due to crimes, and an additional $390,000-$580,000 was estimated to be the value of lost productivity due to dropping out of high school. If a youth was a heavy drug abuser, his/her costs to society ranged between $840,000 and $1.1 million, although $700,000 of this amount was the cost of crime committed by heavy drug abusers (already included in the crime-cost estimates.). The study also estimated the value of saving a high-risk youth at various ages; for example, programs that target first-time juvenile offenders can use estimates based on age 14 ($3.2-$5.8 million). Other programs, however, target early childhood, based on mothers with a high risk for poor parenting. Interventions that encompass the period from birth through early childhood education range in cost between $2.6 and $4.4 million. One of the most important findings, however, is that although juvenile offending behavior accounts for a small fraction of total costs, if these juveniles can be prevented from becoming career criminals, savings may be enormous. The cost-estimation approach used in this study follows and builds upon the early framework and basic methodology developed by Cohen (1998). This involves new estimates of the factors related to the cost of criminal careers, drug abuse, and lost wages and productivity. 1 figure, 12 tables, and 55 references