An emerging issue in stroke prevention and stroke treatment is that therapies shown to be effective in clinical trials are not being used or are being used suboptimally. One of many explanations relates to cost, ranging from concerns about inappropriate use of societal resources to more immediate concerns of organizations and individuals about their financial well-being. Assessing the cost impact of a new therapy, and thus the financial incentives faced by decision-makers, is crucial to understanding and influencing real- world treatment decisions. Assessing cost in the context of health benefits is the object of cost-effectiveness analysis. A cost-effectiveness analysis typically compares the new treatment with a less efficacious yet less costly alternative. This article provides a brief overview of the cost implications of stroke and stroke-related treatments. The example of stroke prevention is used to illustrate how to calculate an incremental cost-effectiveness ratio and help clarify what makes a treatment an especially good value. Because stroke is tremendously expensive and because severe strokes are especially expensive, treatments to prevent stroke and to diminish stroke disability are likely to be an excellent value.