1,1,2-trialkoxyethanes I ##STR1## where R.sup.1, R.sup.2 and R.sup.3 are each C.sub.1 -C.sub.8 -alkyl and R.sup.1 and R.sup.2 may furthermore be bonded to one another to form a 5-membered to 7-membered ring, are prepared by reacting a formaldehyde dialkyl acetal II with carbon monoxide and hydrogen, from 0.5 to 1.5 moles of hydrogen being used per mole of carbon monoxide, and with not less than 1 mole of alcohol R.sup.3 OH per mole of formaldehyde dialkyl acetal under superatmospheric pressure and at elevated temperatures in the presence of a catalyst which is formed from a cobalt carbonyl compound and a trivalent organic compound of the formula III ##STR2## where A is phosphorus, arsenic, antimony or bismuth and R.sup.4, R.sup.5 and R.sup.6 are each an organic radical.