The least-restrictive-alternative guideline for providing treatment emphasizes the use of non-aversive procedures to reduce maladaptive behaviors in individuals with intellectual disability (ID). Differential reinforcement (DR) is an excellent example of such a non-aversive, reinforcement based behavioral intervention. The purpose of this literature review was to summarize and provide a methodological analysis of studies, conducted between 1980 and 2009, using a DR contingency to reduce problem behaviors in adults with ID. A total of 31 studies were located that met the inclusion criteria. Of these, 15 reported DR to be an effective intervention when used independently. Of the remaining, 10 studies found DR to be useful as part of a treatment package, and six found a DR contingency used independently to be ineffective, and only observed treatment effects when an aversive component was added. Very few studies assessed the use of DR in older adults and in individuals with mild ID; these reflect areas of future research. A methodological analysis found that several studies did not report information on key methodological variables; for example, conducting a functional analysis and a stimulus preference assessment to guide choice of treatment and reinforcers, thinning very dense DR schedules, assessing collateral behaviors, generalization of behavior change across settings and implementers, and following up treatment outcomes over time. The overall positive findings about the effectiveness of DR are encouraging; however, more methodologically robust studies would serve to make such findings more conclusive and practically relevant for implementation in natural settings for adults with ID. (Contains 2 tables.)