The invention relates to a process for the preparation of alcohols by hydrogenation of aldehydes, in which use mixture comprising at least one aldehyde and at least one accompanying component is brought into contact, in the presence of hydrogen, with a heterogeneous catalyst, giving a product mixture which comprises at least the alcohol corresponding to the hydrogenated aldehyde, and at least one by-product, where the catalyst comprises a support material, and nickel and copper applied thereto. The invention also includes a chromium-free catalyst suitable for hydrogenating aldehyde mixtures with different chain lengths, in particular those which originate from different hydroformylations and can also comprise substances with C═C double bonds.