To describe the development and implementation of a social peer-mentoring program for persons with traumatic brain injury (TBI) and to explore whether this program yielded increased social functioning outcomes compared with wait-list (WL)controls. Pilot randomized controlled study. Community-dwelling individuals with TBI(12 matched with social peer mentors and 18 completing the WL condition). Trained social peer mentors (SPMs)were matched to partners with TBI (peer partners (PP)) to foster skill-building in planning of social activities and improving social communication abilities through phone contacts and joint participation in social events within the community over a 3-month period. Social Activity Interview, Center for Epidemiological Studies Depression Scale, UCLA Loneliness Scale, Satisfaction with Life Scale, 6-Item Interpersonal Support Evaluation List (baseline and postmentoring); weekly social activity data(1-month baseline, continuously collected during 3-month mentoring or WL period); satisfaction survey. Both SPM and PP participants reported high satisfaction with the mentoring program. Statistically significant improvements in perceived social support after mentoring were observed for the mentored group than for WL participants; however, an increase in depressive symptoms was also observed. While significant improvements in social activity level and social network size were not found, a trend toward increased satisfaction with social life was present for mentored participants. Satisfaction ratings for the SPM program were uniformly high and selected positive findings encourage further investigation of social mentoring as an intervention to effect improvements in social integration. Small sample size and reduced "dosage" of mentor interactions were limitations of this pilot study. Benefits of and challenges to implementation of an SPM program are outlined.