To prevent individuals with traumatic brain injury (TBI) from becoming socially isolated, various forms of group training have been tried. We have implemented group training for chronic-phase TBI in the form of psychiatric day care. In this study, we examined the effectiveness of day care based group training for 20 cases. The results of a caregiver questionnaire after 6 months training indicated that significant improvement was noted in both psychological aspects (in terms of depressive moods and excitement) and in behavioral aspects (understanding of others' feelings and personal appearance). This group training system might improve patients' motivation and communicative ability. These results suggested that day care based group training for TBI was effective in both psychological and behavioral aspects.