The aim of the study was to develop a sampling method aimed at individual sampling of mercury vapor and subsequent individual exposure assessment of the worker. Hopcalite available from Inowrocławskie Zakłady Chemiczne (in Poland) was found useful for mercury vapor sampling in active and passive individual samplers. However the sampling rate determined for passive sampler in steady-state laboratory chamber cannot be used under fluctuating conditions of mercury vapor concentration and air movement typical for field measurement. In order to check comparativeness of passive and active sampling methods, samples were taken in the same time and individual samplers fixed to worker's clothes were used. Mercury vapor concentration was measured at two chloralkali industries in Poland and the results were presented. Excessive exposure in both industries was confirmed by finding elevated mercury concentration in urine samples from the workers.