Trihalomethanes (methane derivatives containing chlorine and/or bromine) have been determined in drinking waters in Upper Silesia ± the most industrious and most populated region in Poland. Halomethane content determination is based on Capillary Gas Chromatography (CGC) with Electron Capture Detector (ECD), while these compounds' isolation from waters by Solid-Phase Microextraction (SPME) is based on optical fibres coated with poly(dimethylsiloxane) phase. In liquid phase the microextraction technique was applied to extract the halogenated compounds from the drinking water coming from consumers' taps in the Upper Silesia region. This method showed precision in the range of 3-12% (R.S.D), depending on the compound. The volatile compounds were present in investigated water in the concentration range from a few ppb to sub ppb.