The purpose of the present study was to examine whether Interpersonal Cognitive Problem Solving(ICPS) skill training would enhance interpersonal solving skills and behavioral adjustment of mildly mentally retarded adolescents in the junior and high school. The program used in the present study was shortened and adapted for mildly retarded adolescents from Shure and Spivack(1982) program which was developed to improve the adjustment of children in the intermediate grades 5-6. The subjects were 22 mildly retarded adolescents, and they were assigned to either the experimental(11) or the control group(11). The experimental group were given ICPS training 4 times a week over a period of 8 weeks with a total of 32 sessions in all. The results showed a significant improvement of alternative thinking and consequential thinking in the experimental group compared with the control group. With regard to behavioral ratings by the parents and teachers, there were no significant differences between the groups. The results indicated that the training was effective in increasing the ability to generate alternative solutions and to predict consequences, but the significant improvement of interpersonal cognitive problem solving skills did not lead to noticeable improvement in behavioral adjustment. It was suggested that a longer training period for over-learning, concomitant parent education program, and more behaviorally oriented social skill training combined with the cognitive approach would yield significant training effects, maintenance and transfer.