We performed a prospective trial investigating the feasibility of a double lumen port access in 26 patients with hematological malignancies or solid tumors receiving either standard conditioning (n = 9, median age 49 years (range 19-65)) or dose-reduced conditioning (n = 17, median age 56 years (range 35-66)) followed by allogeneic blood stem cell transplantation. The port system was implanted within 3 months (n = 20, range 7-91 days) before transplantation or as indicated at different time points after transplantation (n = 6, range 28-680 days). Most infusions, including the graft itself and all blood drawings, were performed via the port. Over a cumulative duration of 5622 days (1310 days after standard conditioning (range 56-349) and 4431 days after dose-reduced conditioning (range 49-489)) two port systems of patients receiving standard conditioning were removed due to early postimplantation pocket infection on day 6 and 8 after insertion, respectively. In the dose-reduced conditioning group only one late removal (day 287) of a port was required. Most of the patients in both groups reported less pain and a higher degree of comfort compared to peripheral or central venipuncture. The use of double lumen port access during conditioning and in an outpatient setting after allogeneic hemopoietic stem cell transplantation is feasible and advantageous for both patient and medical staff. Implantation several weeks before the start of conditioning might help in avoiding early infectious complications after conventional myeloablative conditioning.