Stabilized aqueous C.sub.14 -C.sub.22 -alkyldiketene emulsions containing, as essential components:(a) from 10 to 60% w/w of at least one C.sub.14 -C.sub.22 -alkyldiketene,(b) from 1 to 10% w/w of at least one protective colloid and(c) from 0.1 to 20% w/w of at least one ester of formula I ##STR1## in which R.sup.1 and R.sup.2 each denote C.sub.14 -C.sub.22 -alkyl, R.sup.1 differing in this case from R.sup.2 by at least 4 carbon atoms in the alkyl chain, and/or the same or different C.sub.14 -C.sub.22 -alkenyl groups, or at least one ester of the formula R.sup.3 --O--CO--O--R.sup.4 (II), in which R.sup.3 and R.sup.4 are alkyl or alkenyl radicals of from 2 to 22 carbon atoms or at least one urethane of formula III ##STR2## in which R.sup.5, R.sup.6 and R.sup.7 are the same or different alkyl or alkenyl radicals of from 2 to 22 carbon atoms and one of the substituents R.sup.5, R.sup.6 and R.sup.7 contains at least 12 carbon atoms,and showing a ratio of emulsified components (a):(c) from 200:1 to 1:1 and the use of compounds of formulae I to III as stabilizers for the preparation of alkyldiketene emulsions containing at least 10% w/w and preferably from 16 to 40% w/w of emulsified alkyldiketene.