The invention provides a process for continuously preparing polyether alcohols by adding alkylene oxides to H-functional starter substances using a DMC catalyst, comprising the steps of a) preparing a precursor by continuously metering an H-functional starter substance, an alkylene oxide or a mixture of at least two alkylene oxides and the required amount of DMC catalyst into a continuous reactor, b) continuously withdrawing the precursor from step a) from the reactor, c) continuously metering the product from step a), an alkylene oxide different from that in step a) or a mixture of at least two alkylene oxides different from that in step a) and, if appropriate, the required amount of DMC catalyst into a further continuous reactor.