A process for preparing diaryliodonium salts

The invention relates to a method for producing diaryliodonium sulfonates in high yields and with a high degree of purity and then isolating the same, by reacting special diaryliodonium salts with an aliphatic or aromatic sulfonic acid or an alkaline, alkaline earth or ammonium salt of this sulfonic acid in the presence of water and one or more organic solvents which are immiscible or only slightly miscible with water.