A description is given of processes for the preparation of mono- and bisacylphosphines and of mono- and bisacylphosphine oxides and mono- and bisacylphosphine sulfides, which comprises first reacting organic P-monohalogenophosphines or P,P-dihalogenophosphines, or mixtures thereof, with an alkali metal or magnesium in combination with lithium, where appropriate in the presence of a catalyst, and then carrying out the reaction with acid halides and, in the case of the process for the preparation of oxides, carrying out an oxidation step and, in the case of the preparation of sulfides, reacting the phosphines so obtained with sulfur. It is characteristic, inter alia, that the processes are carried out without isolation of the intermediates.