For a better understanding of absorption, distribution, excretion, and metabolism of trichloroethylene the time-course of blood concentration of the vapour and urinary excretion of its metabolites was examined using a pharmacokinetic model. After a single experimental exposure in which four men inhaled 100 parts per million (ppm) of trichloroethylene for four hours an elimination curve showed three exponential components, that is, X=1-0005e(-16.71t)+0-449e(-1.710t)+0-255e(-0.2027t), where X is that blood concentration in mg/l and t the time in hours from 0 to 10. The overall rate constant for the disappearance of trichloroethylene was found to a agree with the theoretical one, estimated by means of a mathematical model for the blood concentration data. A D8- XD plot, developed from a mathematical model for urinary excretion, could also give a good estimate of rate constant for the transfer of trichloroethylene in the body. The rate constant thus estimated from urinary excretion was consistent with data on the blood concentration.