Determination of polycyclic aromatic hydrocarbons (PAH) and polychlorinated biphenyls (PCB) as important contaminants of environment is a task of many control laboratories. Suitable methods of sample treatment and isolation of analytes must be used due to low contents of the compounds in complex matrices. Individual steps of PCB and PAH analyses are mentioned, the main emphasis being put on the published methods of isolation. Treatment of liquid as well as solid samples using, e.g., liquid-liquid extraction, cloud point preconcentration, solid phase extraction including microextraction and extraction disks, application of membranes, accelerated solvent extraction, Soxhlet extraction, supercritical fluid extraction and microwave application is presented. Many of the mentioned processes offer interesting alternatives for isolation, but careful validation is necessary before they are used in laboratory practice.