Perfluoroalkyl iodides reacted with sodium dithionite by radical process to give sulfina-todeiodination products. so it seems possible to trap the intermediary perfluoroalkyl radical chemically.Alkenes were added as the radical trap and the radical addition products of perfluoroalkyl iodides withalkenes were obtained. The products were 1:1 adducts or oligomers. varying according to the natureof alkenes used. The formation and the orientation of the addition of these products showed thatradicals did take part in the reaction. The relative reactivity of addition reaction and sulfinatodeio-dination and the effect of inhibitor on the reaction was also discussed. Perfluoroalkyl iodides reacted with sodium dithionite by radical process to give sulfina-todeiodination products. So it seems possible to trap the intermediary perfluoroalkyl radical chemically. Alkenes were added as the radical trap and the radical addition products of perfluoroalkyl iodides withalkenes were obtained. The products were The formation and the orientation of the addition of these products showed that radiicals did take part in the reaction. The relative reactivity of addition reaction and sulfinatodeio-dination and the effect of inhibitor on the reaction was also discussed.