One of the main global ecological problems is contamination of the natural environment by persistent organic pollutants (POPs). Polichlorinated biphenyls (PCBs) is a group of compounds that belongs to this family of pollutants. Poland, as a European Union member and signatory of international agreements concerning environmental protection, is obliged to regulate the law and intensify work on the control and utilization of biphenyl PCBs. Therefore, the occurence and determination of PCBs in the polish environment (rivers, lakes, sea water and sediments, living organisms and food chains), and the toxicity and degradation methods of these POP compounds is still important.