The present invention provides a process for preparing a desired halogenated ester, which process comprises the steps of: (a) contacting (A) a substantially organic solvent free liquid mixture of (i) an alkanolate of the formula M—O—Z, wherein M is an alkali or alkaline earth metal, and Z is a linear, branched or cyclic alkyl group of 1 to 10 carbon atoms and (ii) a diester with (B) a halogenated ethylenically unsaturated olefin at a temperature of not more than 40° C. and with a mol ratio of halogenated ethylenically unsaturated olefin to alkanolate of not more than 1.1; (b) contacting an acid with a thus obtained reaction mixture thereby obtaining a mixture comprising the desired halogenated ester; and (c) recovering the halogenated ester from said reaction mixture. In step (a) of the process, the mixture of the alkanolate and diester is contacted with the halogenated ethylenically unsaturated olefin under conditions of agitation sufficient such that the weight ratio of halogenated ester to halogenated ketone as a byproduct obtained after step (b) is at least 10:1.