This study tests the hypothesis that the negative relating of men with a forensic history can be reduced by psychotherapeutic intervention. The Person’s Relating to Others Questionnaire (PROQ), a measure of negative relating, was administered to two male forensic therapy samples, one in a medium secure unit and one in a prison therapeutic community. In the first it was given at assessment prior to admission, at three and nine months after admission, and at follow-up, one year after discharge. In the second it was given on admission, after nine months, and after 18 months. There were significant improvements in mean scores on a number of scales in both samples. Over a fifth of both samples demonstrated reliable improvement. In both samples the major improvement in mean scores occurred relatively early in the period of stay, and thereafter the improvement was sustained. In the first sample, it was still apparent at follow-up.