S-Trifluoroacetoxy-trihalomethyl mercaptans were prepared by reacting metal salt of trihaloacetic acid with perhalomethyl mercaptans in the closed vessel. And besides, certain decomposed states of these products by heat and U.V. were studied by Infra red, N.M.R., molecular weight determination and chemical analysis methods. The results showed that the more fluorine substituted compounds were more stable than the less fluorine substituted ones.