Purpose: To evaluate the safety and efficacy of the radiologic placement of implantable chest ports under intravenous sedation in pediatric patients with malignancy. Materials and Methods: Between October 2001 and June 2002, 20 chest ports were placed in 19 pediatric patients [13 boys and six girls aged 1-11 (mean, 4.7) years] for the purpose of long-term chemotherapy. In three patients, tunneled central venous catheters had been removed because of catheter extraction, infection, and tearing. Under intravenous sedation, the right internal jugular vein was used for access in 19 cases, and the left internal jugular vein in one. Venipucture was performed using a micropuncture needle with real-time ultrasound guidance. A port chamber was created at the infraclavicular fossa, and to prevent catheter kinking, a smooth-angled tunnel was created between the venipuncture site and the subcutaneous pocket. The catheter tip was positioned under fluoroscopy at the junction of the superior vena cava and right atrium. We observed techincal success, complications arouse during and after the procedure, and duration of catheter use. Results: Implantation of the port system was successful in all cases, though slight hematoma, treated with manual compression, occurred at a chamber pocket in one case. In addition, the port system was removed from one patient because of wound infection leading to dehiscence and catheter malpositiong. A new port system was implanted through the left internal jugular vein. The median period during which catheter use was followed up was 118 (range, 18-274) days. Conclusion: For long-term chemotherapy in pediatric patients with malignancy, radiologic placement of an implantable chest port under intravenous sedation shows a high technical success rate, with few complications. This method may thus be used instead of surgical port placement