We report first results on the controlled radical polymerization of 2,3-epithiopropyl methacrylate (ETMA) also known as thiiran-2-ylmethyl methacrylate. Reversible addition-fragmentation chain transfer (RAFT) of ETMA was carried out in bulk and in solution, using AIBN as initiator and the chain transfer agents: cyanopropyl dithiobenzoate (CPDB) and cumyl dithiobenzoate (CDB). A linear increase of the number-average molecular weight and decrease of the polydispersity with monomer conversion were observed using CPDB as transfer agent, indicating a controlled process. Atom transfer radical polymerization (ATRP) of ETMA was performed under different reaction conditions using copper bromide complexed by tertiary amine ligands and ethyl 2-bromoisobutyrate (EBiB) or 2-bromopropionitrile (BPN) as initiator. All experiments lead to a crosslinked polymer. Preliminary studies in the absence of initiator showed that the CuBr/ligand complex alone initiates the ring-opening polymerization of thiirane leading to a poly(propylene sulfide) with pendant methacrylate groups.