A technique for the exchange of occluded, tunnelled, subclavian venous catheters reusing the existing tunnel is described. It was successfully used 14 times in 5 patients needing permanent parenteral nutrition at home, in whom insertion of a new catheter by another route would have been cumbersome and hazardous. The tunnel was opened below the clavicle, and the catheter clamped. The catheter was then cut close to the tunnel exist, and its distal part removed centrally through the opening at the clavicle. A guide wire was simultaneously pulled through. An introducer cannula was placed over the central part of the catheter into the subclavian vein, and the occluded catheter was withdrawn and a new one inserted. The latter was then guided through the tunnel by the guide wire. The catheter was then fixed, and the wound was closed and dressed. Prophylactic cloxacillin was given i.v. for 3 days. No bleeding, pulmonary embolism, local infection or sepsis were observed.