A process for the preparation of 2,2-bis-hydroxymethyl-butanediol-(1,4) of formula I ##STR1## wherein 4-hydroxybutyraldehyde of formula II ##STR2## and/or 2-hydroxytetrahydrofuran of formula III ##STR3## is/are condensed with formaldehyde in the presence of a basic catalyst and the resulting reaction mixture is then catalytically hydrogenated, and 2,2-bis-hydroxymethyl-butanediol-(1,4) is isolated from the hydrogenation product.