Conducted a critical evaluation of both laboratory and field studies that have employed commitment procedures to change behavior. An analysis of the methodological and historical background of research is presented, including the major differences between the behavioral and attitudinal approaches to the study of commitment. This is followed by a review of current research applications in several areas, including behavioral contracting, prosocial behavior, energy conservation, bus ridership, and recycling. The evidence indicates that commitment can change behaviors, especially in the case of resource conservation. Commitment is also effective in maintaining such behaviors.