To provide a method for preparing alkylene oxide adducts having a high degree of narrowness.

This method for preparing alkylene oxide adducts comprises effecting the addition reaction of an active hydrogen-containing organic compound (e.g. a fatty acid higher alcohol) to an alkylene oxide (e.g. ethylene oxide and/or propylene oxide) in the presence of a catalyst containing a dehydrated hydrotalcite compound retaining a layer structure which can be obtained by the dehydration treatment of a water-containing hydrotalcite compound having a layer structure at a temperature of 100°C to lower than 200°C.