Abstract: Production of dialkylthiophosphates of the general formula: ##EQU1## IN WHICH R.sub.1 and R.sub.2 stand for identical or different linear and/or branched alkyl radicals having from 1 to 6 carbon atoms, M stands for a metal cation and n stands for the valence of the metal cation concerned, wherein O,O-dialkylphosphites of the general formula: ##EQU2## in which R.sub.1 and R.sub.2 have the meanings given above, are reacted with a compound yielding the metal cation M, in the presence of pulverulent sulfur and organic solvents at elevated temperature, More particularly, high-grade and very pure dialkylthiophosphates are produced by using, as the compound yielding the metal cation M, the oxide of the corresponding mono- to tetravalent metal.