We conducted functional analyses of two individuals' aggressive behavior. Results of each of the initial functional analyses were inconclusive with respect to the role of social reinforcers in the maintenance of the behavior. Further assessment was conducted to clarify the role of social reinforcers. One individual's results suggested social reinforcers were relevant while results for the second individual remained inconclusive. Treatment evaluations conducted with both individuals suggested manipulation of social consequences could be used to reduce aggressive behavior even though, in one case, no clear social function was apparent. (Contains 4 figures.)