The arylsulphatase activity (E. C. 3. 1.6. 1.) was compared in different species ol Antarctic mammals, birds of the genus Pygoscelis, fish of the genus Notothenia and two crustaceans oi the genus Euphausia. The role of arylsulphatase in the hydrolysis of sulphate phenol esters was pointed out. Considerable differences were observed in the arylsulphatase activity both within genera and species. But no differences in the activity of the enzyme examined were observed in relation to the sex or maturity stage of gonads of chosen Antarctic animals. The activity of arylsulphatase from liver and hepato- pancreas homogenates оf Antarctic animals was lower than the activity of this enzyme in similar animals of the temperate zone.