A process for the preparation of aromatic aryl chloroformates of the general formula I ##STR1## in which Ar denotes an aryl radical optionally mono- to penta-substituted by C.sub.1 -C.sub.20 -alkyl, C.sub.2 -C.sub.20 -alkenyl, C.sub.3 -C.sub.8 -alkyl-cycloalkyl, C.sub.1 -C.sub.20 -haloalkyl, C.sub.1 -C.sub.20 -alkoxy, C.sub.1 -C.sub.20 -alkylthio, halo, cyano, C.sub.2 -C.sub.20 -alkylcarbonyloxy, C.sub.3 -C.sub.20 -carboalkoxy, formyl, C.sub.2 -C.sub.20 -dialkylamino, aryl, aryloxy, arylthio, aroyl, C.sub.7 -C.sub.20 -aralkyl, C.sub.7 -C.sub.20 -aralkoxy, arylsulfonyl and/or C.sub.7 -C.sub.20 -aralkylthio and/or optionally mono- or di-substituted by chloroformyl and/or nitro, from phosgene and phenols of the general formula IIAr--OH (II),in which Ar has the meanings stated above and optionally carries one or two hydroxy groups, wherein the reaction is carried out at a temperature of from 60.degree. to 180.degree. C. in the presence of an organic phosphorus compound of the general formula III ##STR2## in which at least one of the radicals R.sup.1, R.sup.2, and R.sup.3 stands, irrespective of the others, for --NR.sup.5 R.sup.6 or --O--R.sup.7 andR.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7 independently denote C.sub.1 -C.sub.20 -alkyl, C.sub.2 -C.sub.20 -alkenyl, halo, aryl, or C.sub.7 -C.sub.20 -aralkyl and R.sup.1 and R.sup.2, R.sup.1 and R.sup.3, R.sup.2 and R.sup.3, and R.sup.5 and R.sup.6 each denote a saturated or unsaturated C.sub.2 -C.sub.5 -alkylene chain,X denotes hydroxy, aryloxy, halo, or an inorganic or organic acid anion,R.sup.4 denotes hydrogen or C.sub.1 -C.sub.20 -alkyl or halo when X stands for halo, aryloxy, or aralkoxy,n is equal to 0 or 1, andR.sup.4 and X can together denote oxygen or sulfur.