Abstract: A mixture is made from (i) a tris(dihydrocarbylamino) phosphoroamidite and/or a hydrohalide thereof, (ii) a strong base (e.g., NaOH) in proportions of about 2.0 to about 4.0 moles of (ii) per mole of (i), and (iii) at least one solvent for the base (e.g., H.sub.2 O). To this mixture is added a hydrocarbyl monohalide (e.g., EtBr) in proportions of about 1.0 to about 3.0 moles per mole of phosphoroamidite used in forming the initial mixture, and the resultant reaction produces tetrakis(dihydrocarbylamino)phosphonium halide. The process enables more efficient production of tetrakis(dihydrocarbylamino)phosphonium halides, and is capable of being effectively used in large scale production facilities while satisfying the economic constraints of commercial operations.