In a survey sponsored by the Ministry of Food Agriculture and Forestry of the Federal Republic of Germany the mercury contamination of 759 specimens of fishes from the German fishing grounds were analysed. The determinations were performed by flameless atomic absorption (cold vapour system). -We found for the fishes of greatest economic importance herring, cod, saithe, haddock very low averages of less than 0,1 ppm. The legal limit of 1 ppm was only reached or exceeded by older fishes (ling 1.18 ppm, red-fish 1.09 ppm) and by specific kinds of fishes (shark 3.23 ppm, ray 1.69 ppm, tuna 0.80 ppm). -The organically bound mercury (methyl-Hg) which is considered especially toxic, has been determined by gas-liquid-chromatography. Methyl-Hg constitutes about 70--98% of the total mercury, a value which is in agreement with Japanese and Swedish reports on this subject.