Reactions of mono- and bicyclic enol ethers with I-2-H2O2, I-2-(BuOOH)-O-t, and I-2-tetrahydropyranyl hydroperoxide systems have been studied. It was shown that the reaction pathway depends on the nature of peroxide and the ring size. The reaction of 2,3-dihydrofuran and 3,4-dihydro-2H-pyran with the I-2-hydroperoxide system affords iodoperoxides, alpha-iodolactones, and alpha-iodohemiacetals. Bicyclic enol ethers are transformed into vicinal iodoperoxides only in the reaction with the I-2-H2O2 system, whereas the reaction with I-2-ButOOH gives the hydroperoxidation product.