The aim of this study was to investigate the integration of Jigsaw II Cooperative Learning technique in the Life Curriculum and its effect on elementary school second graders' interpersonal communication skills. The subjects were 21 male and female elementary school second graders in New Taipei City, who participated in a weekly 3-period Jigsaw II-integrated Life Curriculum for 10 weeks. This study was based on a mixed methods research design, and data from learning journals and teaching diaries was collected for a qualitative analysis. A quantitative pretest and post-test were measured using an Interpersonal Communication Scale (ICS). The results showed that cooperative learning did effectively enhance students' interpersonal communication skills, and it had a more significant positive effect on the male subjects' interpersonal communication skills than those of the females. It also enabled students with different levels of academic performance to improve their interpersonal communication skills. It was also found that hands-on courses effectively improved students' confidence in expression, while learning in a group enhanced their ability to collaborate effectively.