Based on Peplau's interpersonal theory, Kim developed interpersonal caring techniques (ICTs) that may be used to motivate patients in the community to gain vitality in life and help them care for themselves. ICTs are intended to help patients feel better and gain creative energy through the nurses' love and attention. ICTs include eight techniques: noticing, participating, sharing, active listening, companioning, complementing, comforting, and hoping. This study used a quasi-experimental, pretest/posttest design to assess the effects of nursing interventions using ICTs on the mentally ill. There were two experimental groups (ICT and non-ICT) and one control group. Statistical analysis showed that compared with the non-ICT and the control group, the ICT group showed significant improvement in self-care, interpersonal relationships, and social functioning between pretest, 6 months later (post 1), 12 months later (post 2), and 24 months later (post 3). Additional data from family members also support the above results. These results suggest that ICTs are effective in rehabilitating the mentally in.