The process for preparing alkynediols of the formula (I) R1R2C(OH)—C≡C—C(OH)R1R2  (I) where R1, R2 are each independently H, or a C1-20-hydrocarbon radical which may be substituted by one or more C1-6-alkyls and/or be interrupted by nonadjacent heteroatoms and/or contain C—C double or triple bonds, by reacting compounds of the formula (II) R1—C(═O)—R2  (II) with acetylene in a polar aprotic solvent is carried out in the presence of basic alkali metal salts as catalysts.