An improvement in the process for preparing an orthoacetic acid alkyl ester of the formula ##STR1## wherein R is a saturated, branched or un-branched, alkyl moiety of 1 to 8 carbon atoms by:(a) contacting acetonitrile with an anhydrous alkanol having 1 to 8 carbon atoms and dry hydrogen chloride in the presence of an organic solvent to prepare the corresponding imidoester hydrochloride;(b) thereafter contacting said imidoester hydrochloride in the acid-free state with an alkanol having 1 to 8 carbon atoms; and(c) removing by-product ammonium chloride from the resultant reaction mixture and distilling the reaction mixture to recover orthoacetic acid alkyl ester, the improvement residing in(d) employing as the organic solvent an inert solvent having a dielectric constant measured at 25.degree. C. of 2.6 or less; and(e) contacting said imidoester hydrochloride in step (b) with an alkali metal or alkaline earth metal alcoholate before contacting the same with said alkanol.Also disclosed is a process in which steps (a) and (b) are performed coterminously without isolation or recovery of the intermediate imidoester hydrochloride.