A process for producing dimethyl terephthalate from high-boiling tarry residues from the combined oxidation of p-xylene and p-toluate in the liquid phase, esterification of the resulting acids with methanol and separation of the resulting dimethyl terephthalate which include the steps of subjecting the high-boiling residues to treatment with methanol at temperatures above 250.degree. C. and thereafter separating the resulting dimethyl terephthalate in accordance with conventional separation techniques.