Background In a recent trial, a 6-session intervention (BMT-CARE) integrating medical information with cognitive-behavioral strategies improved quality of life (QOL), mood, coping skills, and self-efficacy for family/friend caregivers of hematopoietic stem cell transplantation (HCT) recipients. This study examined whether improvements in coping and self-efficacy mediated the intervention effects on QOL and mood.