Cost data are a fundamental component of health economic analyses, consisting of two core elements: the quantity of resources used (such as veterinary visits) and the unit price of those resources (e.g., the cost per visit). While total treatment costs may sometimes be available, the micro-costing approach, i.e., estimating each component of resource use and then applying corresponding unit prices, is widely considered the most accurate method. Unit prices can be obtained from sources such as statistical databases, agricultural records, tariff lists, pharmaceutical price lists, and other published sources. However, determining resource use is often more challenging. The types of cost data that need to be collected depend on the perspective of the analysis. The societal perspective, which considers all costs and benefits, is the broadest and is particularly relevant for decisions on global animal health programs. For individual treatment decisions, the perspective of the animal owner or herd manager is typically more appropriate. Historical prices require inflation adjustment, and costs that accrue in following years need to be discounted to the present value. A conservative approach, i.e., biasing uncertain cost data in disfavor for the intervention of interest enhances credibility.