One hundred forty-three large bore right-atrial catheters (RACs) in 111 bone marrow transplant recipients were prospectively analyzed for the incidence of complications interfering with catheter function. Of the 143 RACs, 108 (76%) were patent on departure from Seattle or death. Infectious complications occurred in 63 (44%) of the catheters, resulting in 18 (13%) removals. Noninfectious complications occurred with 54 (38%) of the catheters, resulting in 17 (12%) removals. Successful interventions included catheter repair, dissolving precipitates with ammonium chloride solution, and declotting catheter lumens with heparin and/or urokinase. We conclude that RACs continue to be reliable and safe devices to use in marrow transplant patients. Complications interfering with catheter function are frequent; however, most can be resolved without the need to remove the catheter.