To investigate new approaches for treatment of drug abuse, subcutaneous vascular ports were implanted in rhesus monkeys (Macaca mulatta) for use in drug self-administration studies. Internal or external jugular veins were cannulated, and the catheter was attached to a subcutaneous port that was positioned on the back between the shoulder blades. This port/catheter system allowed easy serial blood sampling and intravenous drug administration. Daily use of the ports in awake monkeys was simple, effective, and caused no apparent stress over a 2-h experimental session. At the time of submission, the mean functional lifetime of the port/catheter system in 20 monkeys implanted longer than 6 months was 243.61 days, with the upper range being 540 days. Several complications developed with this system, and solutions to these problems are described. With proper aseptic use, the subcutaneous vascular port system provided a safe and enduring method for daily access for intravenous sampling and/or drug delivery. The duration of the preparation is a considerable improvement compared with exteriorized catheterization.