This study aims to determine the total costs after allogeneic hematopoietic stem cell transplantation (ASCT) and factors associated with increases or decreases in costs.We collected all in- and outpatient costs during 5 years in 93 patients who had undergone ASCT in 1998 and 1999 at our unit. The inpatient costs included all those related to a patient from the first day of admission until discharge and then all costs of readmission in the Stockholm area.The total median cost of five posttransplant years was 139,414 (52,095-345,640) euros (euros) or 167,296 US dollars (the rate of 1 euro is approximately 1.2 US dollars). The costs were highest during the first year-median inpatient and outpatient costs 100,650 euros and 13,066 euros, respectively. The total costs during the first year were higher in patients with acute graft-versus-host disease grades III-IV (relative hazards [RH] 1.35, P = 0.003), bacteremia (RH 1.33, P = 0.005), veno-occlusive disease of the liver (RH 1.32, P = 0.005), prophylaxis with granulocyte colony-stimulating factor (G-CSF; RH 1.31, P = 0.01), acute leukemia (RH 1.32, P = 0.008), and treatment in hospital instead of at home (RH 1.20, P < 0.07). During the early transplant period, a second transplantation (RH 1.28, P = 0.014) and hemorrhagic cystitis (HC; RH 1.24, P = 0.03) were also associated with higher costs. The total 5-year cost declined with longer survival rates (r = 0.4028, P < 0.001) and reduced intensity conditioning (RH 0.79, P=0.024).Higher costs of ASCT were associated with retransplantation, acute leukemia, G-CSF prophylaxis, hospital care, myeloablative conditioning, and major transplant-related complications.