A method for the implantation of catheters into carotid, jugular, and femoral vessels that allows long-term access in conscious dogs has been described. The vascular catheters, especially when introduced into the femoral vessels, remain patent for more than 12 months. This improved patency may result from the solving of several methodological problems: 1. firm securing of the catheters to the vessels with a simple polyethylene perivascular muff that is rapidly prepared and introduced; 2. a 5 cm long replaceable catheter connected to the free end of the intravascular tubing prevents the need to replace the entire implantation after crushing; 3. a leather jacket, together with a large leather collar in some cases, prevents the animal from damaging the free ends of the catheters that lie longitudinally along the back. In addition, they allow rapid healing of the incisions, particularly in the thigh.