Allogeneic hematopoietic cell transplantation (HCT) recipients have substantial transfusion requirements. Factors associated with increased transfusions and the extent of blood product use in umbilical cord blood (UCB) recipients are uncertain. We reviewed blood product use in 229 consecutive adult recipients of allogeneic HCT at the University of Minnesota: 147 with leukemia, 82 lymphoma or myeloma; 58% received unrelated UCB and 43% sibling donor peripheral blood stem cell (PBSC) grafts. Although neutrophil recovery was prompt (UCB median 17, range: 2-45 days, and PBSC 14, range: 3-34 days), only 135 of 229 (59% cumulative incidence) achieved red blood cell (RBC) independence and 157 (69%) achieved platelet independence by 6 months. Time to platelet independence was prolonged in UCB recipients (median UCB 41 versus PBSC 14 days) and in patients who had received a prior transplant (median 48 versus 32 days). Patients who received UCB grafts required more RBC through day 60 post-HCT (mean UCB 7.8 (95% confidence interval [CI] 6.7-8.9) versus PBSC 5.2 (3.7-6.7) transfusions, P = .04), and more platelet transfusions (mean 25.2 (95% CI 22.1-28.2) versus 12.9 (9.4-16.4), P < .01) compared to PBSC recipients. Patients receiving myeloablative (MA) conditioning required more RBC and platelet transfusions during the first 2 months post-HCT compared to reduced-intensity conditioning (RIC) (7.4 versus 6.2, P = .30 for RBC; 23.2 versus 17.5, P = .07 for platelets). Despite prompt neutrophil engraftment, UCB recipients had delayed platelet recovery as well as more prolonged and costly blood product requirements. Enhanced approaches to accelerate multilineage engraftment could limit the transfusion-associated morbidity and costs accompanying UCB allotransplantation.