Abstract: Disclosed are aminated acetate fiber comprising acetylcellulose and one or more water-insoluble quaternary starch ether esters, said starch ether esters containing ester groups of formulae --O--CO--CH.sub.3 and/or --O--CO--C.sub.2 H.sub.5 and ether groups of the general formula I--O--CH.sub.2 --X--CH.sub.2 --N.sup.+ R.sub.3 A.sup.- (I)whereX is a direct bond or --CH(OH)-- andA.sup.- is an anion or one equivalent of an anion, andR is hydrogen, methyl and/or ethyl,and the degree of substitution of said ether group being within the range from 0.002 to 0.8, the degree of substitution of said ester group being within the range from 0.7 to 2.998 and the overall degree of substitution being within the range from 1.5 to 3, its preparation and its use and also quaternary starch ether esters present therein.