Economic evaluations of health-care technologies are playing an increasingly central role in determining which therapies are available to clinicians in the treatment of a whole range of conditions. In rheumatology, a large body of work has already been done on the cost effectiveness of alternative non-steroidal anti-inflammatory drugs (NSAIDs), and much of the current work on disease modifying therapies incorporates economic evaluations. This chapter describes the main techniques of economic evaluation and reviews the strengths and weaknesses of each. Two published economic evaluations are discussed in order to highlight what economic evaluations can offer to the care of people with rheumatoid arthritis, as well as the current limitations of economic evaluation. The objective of this chapter is to equip readers with a critical understanding of economic evaluation that can be used in considering the increasing volume of health economic data that they encounter in their clinical work.