There is much interest in understanding the biokinetics of zirconium in humans due to the potential radiological risk represented by the radionuclide 95Zr and by its daughter 95Nb. Despite the significance of zirconium, few data are available on the actual biokinetics of zirconium in humans. Accordingly the biokinetic model currently recommended by ICRP for this element is based mainly on data from animal experiments. In this study, the use of the stable isotopes 90Zr and 96Zr as tracers has enabled the conduct of 6 biokinetic investigations in 3 healthy volunteers. These studies have provided new valuable information about intestinal absorption and kinetics in blood plasma of zirconium and have been used for the set-up of a more realistic compartmental model with possible applications for dosimetric purposes.