The article discusses the use of cost-benefit analysis to assess conservation efforts, and applies this technique to Venezuela's National Parks Systems to assess how much Venezuela should spend in managing its National Parks. As with any major environmental decision, this calls for more than economic criteria. Social values, science and politics all affect environmental decisions, and economics should be but one factor considered. Nonetheless, cost-benefit analysis provides a valuable tool and a framework for improved understanding of the tradeoffs among different factors.