A retrospective analysis of 33 patients with malignancy and thrombocytopenia of less than 100,000/microliter who underwent percutaneous Silastic (Evermed) catheter insertion is presented. Thirty-seven catheter insertions were performed in these patients during a 2-year period. The insertion technique includes intraoperative platelet transfusion for patients with platelet counts of less than 50,000/microliter, the use of general anesthesia for infants and children, and intravenous sedation with local anesthesia in adults. Minimizing the dissection required for the subcutaneous catheter tunnel is achieved with a modified shunt-tunneling device. The majority of catheters were placed by the subclavian approach. Fifty-nine percent of the procedures took place when the platelet count was less than or equal to 30,000/microliter. There was no mortality related to the procedure. Four complications directly related to the technique (arterial puncture, 3; cervical hematoma, 1) and eight related to the catheter occurred without serious sequelae. With appropriate precautions, percutaneous placement of Silastic catheters can be performed safely in patients with thrombocytopenia. This technique produces less tissue injury than operative venotomy, may be performed more rapidly, obviates sacrifice of the vein that is used and, consequentially, allows for multiple subsequent insertions via the same vein.