A route for preparing block copolymers by the combination of cationic and free radical photopolymerization is examined. For this purpose, a growing polyepichlorhydrin (PECH) chain, prepared by using HBF(4) as an initiator, was terminated by the addition of the sodium salt of N,N-diethyl dithiocarbamate. PECH possessing a thiuram disulfide group at the chain end thus obtained was used in the photo-induced polymerization of styrene to yield active poly(epichlorhydrin-b-styrene) block copolymers. These active block copolymers were also used in the photopolymerization of methyl methacrylate to obtain ABC-type triblock copolymers. The block copolymers were characterized by spectroscopic methods, fractional precipitation, and gel permeation chromatography.