Burvin, R., M. Zloczower and E. Karnieli. Double-vein jugular/inferior vena cava clamp technique for long-term in vivo studies in rats. Physiol Behav 63(4) 511-515, 1998. We present a step-by-step manual for chronic cannulation of rats using a simple technique. This concept facilitates repeated clamping of the same rat over a 6-10-week period, providing a completely separate infusion route from blood sampling access which is placed into mixed venous blood in the inferior vena cava. Permanent catheters implanted into the left external jugular vein and the inferior vena cava were used for miniature blood sampling and recycling. The design and running of clamp experiments and other physiological research models are detailed. Long-term reliable venous access, simple installation, and easy after-care of the rats cannulas are the principal advantages of the procedure described.