OBJECTIVE To describe the use of a modified 15.5-Fr double-lumen, tunneled right atrial catheter (Hickman-Crawford catheter) in adult bone marrow transplant recipients, that permits passage of a 5-Fr pulmonary artery catheter through the larger of the catheter's lumens. METHODS A case series review of the clinical experience with a modification of the existing central venous catheter design. METHODS A bone marrow transplantation center. METHODS Fourteen patients (weighing at least 50 kg body weight) undergoing bone marrow transplantation. Ages ranged from 18 to 64 yrs (median 40). There were nine male and five female patients. All patients, except for three who were receiving autologous marrow transplants, underwent allogeneic transplants. RESULTS Sixteen catheters were inserted into the subclavian vein in 14 patients. The catheters remained in place for a mean of 44 days (median 30; range 6 to 107) and 56% remained functional until removed an average of 60 days later at the time of death (n = 5) or discharge to home (n = 4). One catheter was accidentally dislodged by the patient and six catheters (38%) were electively removed, two because of infection and four because of mechanical occlusion or damage. The Hickman-Crawford catheter was used as venous access for insertion of 21 pulmonary artery catheters in 12 patients (twice in seven patients). Ninety percent of these insertions (19 of 21) were done without difficulty; use of a guidewire was required in the remaining two cases. No complications of pulmonary artery catheterization were seen. CONCLUSIONS This experience illustrates that a tunneled right atrial catheter for long-term use can be employed safely and repeatedly for insertion of pulmonary artery catheters for central hemodynamic monitoring.