By the reactions of olefins with an equimolar mixture of SbCl5 and I2 in carbon tetrachloride, various chloroiodoalkanes are obtained in fair to good yields. This method is applicable to various deactivated olefins, the reactions of which do not proceed by the reported method using a mixture of CuCl2 and I2. Iodine monochloride can aslo be used for this reaction, but in this case both the yield and