Process for the preparation of unsaturated alcohols and/or esters thereof by reacting conjugated dienes with water and/or aqueous carboxylic acid solutions in the presence of a macroporous acid ion exchanger and suitable solvents. The diene has the general formula I ##STR1## in which R.sup.1, R.sup.2 and R.sup.3 are hydrogen or a methyl group and R.sup.2 also can represent an aliphatic hydrocarbon radical having 2 to 6 carbon atoms which may contain a double bond which is not in a conjugated position relative to the double bonds of the diene, and preferably R.sup.1 and R.sup.3 each represent groups CH.sub.3 or CH.sub.2 --CH.sub.3. Said diene is reacted in a homogeneous or quasi-homogeneous phase in the presence of said macroporous acid ion exchanger.