Method for producing tertiary phosphines by reacting a compound of the general formula (I) in which A is R1 or L2, B is R2 or L3, the R1 and R2 radicals are each independently an organic radical having in each case from 1 to 30 carbon atoms, where the R1 and R2 radicals may also be joined together; and the leaving groups L1 to L3 are each independently halogen, alkyloxy having from 1 to 10 carbon atoms or aryloxy having from 6 to 10 carbon atoms (a) with an alkali metal in an organic aprotic solvent and (b) a compound of the general formula (II) L4-R3   (II) in which the R3 radical is an organic radical having in each case from 1 to 30 carbon atoms; and the leaving group L4 is halogen, alkyloxy having from 1 to 10 carbon atoms or aryloxy having from 6 to 10 carbon atoms, in which the resulting reaction mixture is hydrolyzed with an aqueous base which has a pH of ≧10 and the organic phase is removed from the aqueous phase.