Palifermin, a recombinant human keratinocyte growth factor, is commonly given to prevent mucositis following autologous transplantation. In the allogeneic hematopoietic stem cell transplant (allo-HSCT) setting, safety and efficacy data are limited. We conducted a retrospective study in 251 patients undergoing allo-HSCT, 154 of whom received peritransplant palifermin. In all patients, palifermin significantly decreased the mean number of days of total parenteral nutrition (TPN, 13 vs 16 days, P=0.006) and patient-controlled analgesia (PCA, 6 vs 10 days, P=0.023), as well as the length of initial hospital stay (LOS, 32 vs 37 days, P=0.014). However, the effect of palifermin was only significant in patients who received a TBI- but not BU-based chemotherapy conditioning regimen. In TBI recipients, palifermin decreased the mean number of days of TPN (13 vs 17 days, P<0.001) and PCA (7 vs 12 days, P=0.033), and the length of stay (32 vs 38 days, P=0.001). Palifermin did not affect GVHD, graft failure or relapse. Therefore, in the largest analysis with this patient population to date, we demonstrate that palifermin is safe in allo-HSCT patients, decreases TPN and PCA use and decreases LOS following TBI-based but not chemotherapy-based allo-HSCT.