If VADs and ECMO are to become part of routine care, they need to demonstrate that they are cost-effective. Otherwise, the time and money they consume would be better spent elsewhere in the health system. A cost-effective therapy is one that provides value for money in terms of the healthy life years gained for the costs incurred. The lives saved by VADs and ECMO need to be balanced against their relatively high cost. In this chapter we explain the key parts of a cost-effectiveness analysis using examples from published studies of VADs and ECMO.