An electron-deficient iron(III) porphyrin complex associated with iodobenzene diacetate (PhI(OAc) 2 ) afforded high yields of oxygenated products in catalytic oxygenations of olefins and alkanes when the reactions were carried out in the presence of a small amount of water. An oxoiron(IV) porphyrin cation radical intermediate was generated in the reaction of an iron(III) porphyrin complex and PhI(OAc) 2 . These results demonstrate that PhI(OAc) 2 , which is soluble in organic media, safe to use, and readily available, is an efficient oxygen atom donor that can be used as a substitute for polymeric iodosylbenzene (PhIO) in metalloporphyrin-mediated oxygenation reactions.