A three-year prospective study was conducted to evaluate right atrial silicone elastomer catheters for long-term venous access in adults with acute leukemia. Objectives included establishing the safety of catheter insertion in thrombocytopenic patients and the feasibility of maintaining the catheter during septicemia. Seventy-one catheters were placed in 57 consecutive patients entering intensive leukemia therapy. Excessive bleeding occurred at three catheter insertion sites. Eight catheter-related infections occurred. In 34 of 36 noncatheter-related and two catheter-related bacteremias, catheters were left in place with intensive monitoring. In 20, bacteremia cleared. Fourteen patients died; in eight autopsies, no evidence of catheter-related mortality was found. Catheters were in use 6,799 days, including 3,932 home use and 2,570 granulocytopenic days. The data indicate that thrombocytopenia does not preclude catheter insertion and that catheters can be safely maintained in septicemic granulocytopenic patients.