We describe a newly developed method of continuous intravenous infusion and simultaneous monitoring of plasma levels of investigational compounds in ambulatory untethered rabbits. Continuous infusion was administered by means of a portable programmable external micropump which permitted adjustable dosing. Simultaneous plasma pharmacokinetic monitoring during infusion was accomplished by dual silastic central venous catheters. The potential applications of the micropump infusion system as an alternative to current methods of continuous infusion in other species and in other studies are further discussed. This method provided a safe, reliable, and well-tolerated method of adjustable continuous intravenous infusion and simultaneous sampling of central venous blood in rabbits.