An experimental study on the kinetics of the reversible addition-fragmentation chain transfer (RAFT) copolymerization of styrene (STY) and divinylbenzene (DVB) is presented. The experiments were carried out in bulk from a mixture of monomers, S-thiobenzoyl thioglycolic acid as RAFT agent, and the initiator dibenzoyl peroxide (BPO) at 80 degrees C. The effect of RAFT agent concentration, including the case without RAFT controller, on polymerization rate, molecular weight development, gel fraction, and swelling index was analyzed.