Acquisition of verbal behavior is a major goal of interventions for children with developmental disabilities. We evaluated the effectiveness of manipulation of an establishing operation for functional discriminated mands. Four individuals with developmental disabilities participated in a training procedure designed to teach two separate mands for two separate preferred items. Participants were taught to mand using picture cards. Following training, the manipulation of the establishing operation was used to assess and establish discriminated manding. This manipulation involved providing free access to one of the preferred items, such that there should be no motivation to ask for it, while motivation to ask for the other item remained in place. Three of the 4 participants acquired discriminated manding using topographically similar responses (picture cards). One participant did not acquire a discriminated mand until topographically distinct mands were taught (vocal and picture card). Results suggest that discrimination training is not necessarily sufficient to teach discriminated manding when more than one picture card showing preferred items is used. In addition, manipulation of the establishing operation served as an appropriate assessment tool for the verification of discriminated manding as well as a possible training tool to establish discriminated manding. (Contains 7 figures.)