This prospective study validates the finding from retrospective research that having an inpatient lay care-partner (CP) is associated with better survival following allogeneic BMT. Compared with patients without a CP (n=76), patients with a CP (n=88) have significantly better OS (P=0.017) and relapse-free survival (RFS) (P=0.020). Four-year and median survivals were 42% and 36 months among patients with CPs, compared with 26% and 10 months among those without CPs. Four-year survival and median RFS were 39% and 25 months among those with CPs, compared with 23% and 7 months among those without CPs. Further, better survival and RFS were associated with CP visit duration of >3 h per day (P=0.005 and P=0.007, respectively) and with CP frequency of visits >75% of inpatient days (P=0.004 and P=0.010, respectively). A CP support program should encourage not only presence of a CP but also duration and frequency of CP visits associated with better patient survival.