The reactions of ozone with iodoethane isolated in argon matrices at 16 K and the subsequent photochemical reactions are reported. A molecular complex between ozone and iodoethane is formed on codeposition, but irradiation at wavelengths longer than 800 nm leads to the formation of the photoproduct iodosoethane, C2H5-IO. Further photolysis with radiation of wavelengths longer than 650 nm yields the photoproduct iodylethane, C2H5IO2. Radiation of wavelengths longer than 350 nm produces ethyl hypoiodide, hydrogen hypoiodide, and ethanal. Subsequent Pyrex-filtered photolysis increases the yield of ethanal. After quartz-filtered photolysis, hydrogen iodide is formed and the yield of ethanal increases. The ethanal so produced forms complexes with hydrogen iodide which can be distinguished by sample annealing. The products were identified by employing deuterated iodoethane, O-18(3), and scrambled ozone ((O3-xOx)-O-16-O-18) made from 50:50 O-16(2)/O-18(2).