Fishes from fish-hatcheries, lakes and the river Oder in the area of the former district Frankfurt (Oder) were analysed for organochlorine pesticides (HCB, aldrin, HCH-isomeres, DDD, DDE, DDT, endrin, toxaphen and dieldrin), polychlorinated biphenyles and penta- and tetrachlorophenole. A clean up-procedure using acidic digestion mixture has been compared with a column-extraction-procedure followed by column chromatography on aluminia. Furthermore the simultaneous determination of the organochlorine pesticides, PCB's and chlorophenoles by acidic silicagel-extraction is described. The identification and quantification was realized by packed-column and capillary-gaschromatography including electron-capture-detection. The investigations show, that the permissible levels were only reached up to 2 to 10% with exception of toxaphen and pentachlorophenole. Average 50% of the toxaphen- and pentachlorophenole-values were found near the tolerance levels settled for these substances. The application of both substances in the area of the former German Democratic Republic until today can be regarded as a reason for this. The results of our investigations are comparable to last publications on fish contamination in the area of the previous Federal Republic of Germany.