We report a method that we have devised in which a secure subcutaneous tunnel is prepared during the placement of an indwelling central venous reservoir in the forearm. Subjects included 69 cases in which a procedure for implanting an indwelling reservoir in the forearm was performed between June 2006 and May 2007. For the subcutaneous tunnel, a 22-G Cathelin needle was advanced from the puncture site, turning toward the subcutaneous pocket side to the deep subcutaneous area. A 14-G Surflo IV catheter was then advanced along the 22-G Cathelin needle from the subcutaneous pocket. With the tip of the 14-G Surflo IV catheter emerging above the skin at the puncture site, the inner needle of the 14-G Surflo IV catheter and the 22-G Cathelin needle were removed. The catheter was passed through the outer 14-G Surflo IV catheter to emerge on the subcutaneous pocket site, then the outer needle of the Surflo catheter was also removed, and a connection to the port was made to create the subcutaneous tunnel. In all 69 cases, the subcutaneous tunnel in the forearm of the nondominant arm was successfully created within a short period of time (100% success rate). No problems were observed due to slack in the catheter until removal of the sutures 1 week later and for 3 months after treatment. With this method, we believe that a subcutaneous tunnel can be prepared in which the contained catheter has minimal freedom of movement, and which minimizes any damage induced by slack in the catheter within the subcutaneous tunnel.