Long-term survivors of hematopoietic stem cell transplants remain at risk of potentially fatal complications that detract from life quality. Long-term morbidity and mortality were compared between matched recipient cohorts surviving 2 or more years and defined by donor type, HLA matched sibling donor (MSD) or volunteer unrelated donor (URD). Patients were previously entered into the prospective multicenter International Unrelated Search and Transplant Study. Thirty-nine centers provided data on 108 URD and 355 MSD recipients surviving more than 2 years. Long-term survival, performance status, chronic GvHD (c-GvHD), secondary malignancy, endocrine dysfunction, cataracts, bone necrosis and dental pathology were compared between cohorts. Twelve year survival was 77+/-5% for the MSD and 67+/-11% for the URD cohort (P=0.1). Late death occurred in 105 of 463 recipients alive at 2 years, 73 after 355 (21%) MSD and 32 after 108 (30%) URD transplants, P=0.10. Of 105 deaths, the cause was relapse in 60 and unrelated to relapse in 45 cases. Cumulative incidence of extensive c-GvHD (P=0.002), cataracts (P=0.02) and bone necrosis (P=0.02) was higher after URD transplants. No long-term difference in endocrine dysfunction, secondary malignancy and major dental pathology was detected. This landmark study will assist physicians counseling patients pre-transplant and with their long-term care post transplant.