The photolysis of vinyl iodide in carbon tetrachloride solutions gives several products among which the most important are: acetylene, hydrogen iodide, iodine, ethylene, and vinyl chloride. A mechanism based on diffusion-controlled disproportionation of geminate radicals, as first proposed by Hamill, agrees well with the observed phenomena. To explain the diminishing production of ethylene and iodine with increasing concentration of the monomer, it is necessary to postulate a telomerization of the vinyl iodide.