Nitroarylacetic acid esters are prepared by reacting a nitroaromatic compound which is devoid of halogen on the aromatic ring carrying a nitro group with an alpha,alpha-disubstituted acetic acid ester in an inert solvent and in the presence of a base so that the ester undergoes a nucleophilic substitution on an unsubstituted ring carbon of the nitroaromatic compound during which an alpha-substituent functions as a leaving group. Nitrobenzene acetic acids and their esters are useful intermediates for the synthesis of pharmaceuticals.