Abstract: A process for preparing tetrahydrofuran, which comprises reacting 1,4-butenediol diethers of the formulae I and/or II RO—CH2—CH═CH—CH2—OR  I RO—CH2—CH2═CH—CH2—OR  II, where the R radicals can be identical or different and are C1-C15-alkyl or cycloalkyl radicals, C6-C12-aryl radicals or C7-C15-aralkyl radicals, with water and hydrogen at from 20 to 300° C. under from 1 to 300 bar in the presence of catalysts or catalyst combinations which comprise components which are both capable of hydrogenation and have acidic or basic centers and a novel process for preparing 1,4-butanediol diethers of the formula I by metathesis are described.