The invention relates to phosphoric esters of the general formula I ##STR00001## where X is 1 or 2; n is from 2 to 18; m and o are each from 2 to 100; k is from 2 to 4; R'' is H or a linear or branched alkyl radical; and R' is an alkyl, alkaryl, alkenyl, or sulfopropyl radical, and to there use as dispersants for pigments and fillers in aqueous or organic media.