This study was concerned with demonstrating that a verbal conditioning technique can be used to modify mental hospital patients' self-evaluations. Essentially, it was a replication, with mental hospital patients, of an earlier study which had shown, with military personnel, that the frequency of endorsement of self-accepting questionnaire items can be increased by standard verbal conditioning techniques and that this increase generalizes to similar but novel items as well as to items indicative of more positive attitudes towards others. Sixty patients, who scored low on a selected portion of a self-acceptance questionnaire, were randomly assigned to experimental and control conditions. Subjects in the former condition were reinforced for accepting responses to 18 self-acceptance items on three successive days, while the latter received no reinforcement. A postexperimental scale, comprising the original 18 self-acceptance items and an additional 32 novel items, was administered to all subjects. The results support the hypotheses and show that attitudes, which are theoretically relevant to social interaction, can be modified by means of verbal conditioning techniques.