Process for preparing monoethylene glycol (MEG) by metal-catalyzed reaction of a dialkyl oxalate of the formula I where R1 and R2 are each, independently of one another, methyl, ethyl, n-propyl or isopropyl, with hydrogen (H2), wherein the dialkyl oxalate (I) is used as melt or as a solution in a solvent, dialkyl oxalate (I) and H2 are used in a molar ratio of H2:dialkyl oxalate (I) in the range from 4.0 to 30 and the reaction is carried out continuously in a reactor at a cross-sectional loading of ≥10 m/s, a temperature in the range from 150 to 270° C., a pressure in the range from 150 to 390 bar and in the presence of a chromium-free heterogeneous catalyst comprising copper.