The evaluation in industrial exposure to volatile organic compounds based on assessing concentrations of unchanged substances in blood of exposed workers seems to gain increasing interest. The main obstacle to a wide application of this method is the difficulty in collecting venous blood samples. Many authors suggest determining volatiles in capillary blood samples because they display the same concentrations as the arterial blood samples. The collection of capillary blood samples is much more convenient in occupational setting than the collection of venous blood samples. The aim of this study was to develop micromethod for determining organic solvents in small blood samples (100 mm3) by gas chromatography with headspace technique. 1.8 cm3 glass vessels (Sapelco) with screw caps, silicone rubber membranes and aluminium foil pads were used. After addition of 0.1 cm3 of blood and 2.0 cm3 of aqueous solution of internal standard, the vessels were closed tightly and shaken for 30 min. at 70 degrees C in water bath. Then about 1 cm3 of the gas phase was sampled with a gastight syringe (Hamilton) injected into the gas chromatograph. The parameters of the recently developed methods for determining organic solvents in blood samples, including linearity, precision, reproducibility, stability and sensitivity, are fully compatible with the principles of biological monitoring.