A method is presented for the determination of insecticides belonging in the group of chlorinated hydrocarbons (organochlorine insecticides) in tobacco and tobacco smoke. The described analytical procedure allows the rapid measurement of insecticide concentrations down to the detection limit of 0.01 ppm. Tobacco or tobacco smoke condensate is extracted with aqueous acetonitrile. The filtered extract is diluted with water, and the insecticide residues are then extracted with petroleum ether. The concentrated petroleum ether extract is chromatographically purified by passage over a Florisil column and, subsequently, eluted with mixtures of diethyl ether and petroleum ether (6 and 15 % of diethyl ether, respectively). After vacuum sublimation the concentrated eluates are qualitatively and quantitatively analysed by gas chromatography using an electron capture detector and by thin-layer chromatography. On an average, 8 % of chlorinated hydrocarbon insecticides contained in tobacco are shown to be transferred into the mainstream smoke.