CHAPTER SUMMARY. Applying estimates of the prevalence of problem and pathological gamblers to the cost estimates of Chapter 7 produces social cost totals. A citizen or local government official also might be interested in knowing the additional social cost of introducing casinos. In this chapter, we report three numbers: first, the implied social cost of problem and pathological gambling on the national level; second, the cost–benefit ratio for the casino industry based on per-adult numbers adjusted to a common base; and third, an estimate of the long-term social costs from introduction of casinos into an economy or region that did not have them previously. On a national basis, the social costs of problem and pathological gambling are between $32.4 billion and $53.8 billion. On a per-adult basis, these translate to $165 to $274 per year, or $219 on average. Comparing the costs of Chapter 7 to the benefits of Chapter 6, adjusted to a common base and including regulatory costs, implies that costs outweigh benefits by a factor between 3.9:1 and 6.3:1. The long-term cost-to-benefit ratio from introducing casinos to a region that did not have them previously is greater than 3:1.