ABSTRACT This study assessed the effectiveness of an intervention program for youthful offenders in Iowa based on a cognitive approach to rehabilitation, which pivots on the theme that "bad thinking leads to bad behavior." Subjects were 16- and 17-year-old juveniles who had been transferred to adult court and 18- and 19-year-old youth who had been arrested for "first time serious felonies." Attitudes towards police and the courts improved during the intervention, as did feelings that the offender's probation officer was supportive. Offender feelings of accomplishment and ability did not improve, and problem-solving ability and prospects for life success apparently decreased, although prospects for improving life goals and offender empathy toward victims changed positively. Three patterns emerged: Changes in attitudes toward the criminal justice system, a sense of personal accomplishment and ability, and a sensitivity to the views of others.