The preparation and adhesion properties of poly(methyl methacrylate-butyl acrylate)[P(MMA-b-BA)] diblock copolymers have been studied. Block copolymers were analyzed by H-1-NMR, DSC, and SEC, and confirm the synthesis of diblock copolymers, using the iniferter route. Investigation of peel strength in laminate joints, reinforced with various block copolymers, suggests that adhesion depends on both molecular weight and composition. When the copolymer contains mainly PMMA block, molecular weight has a marked effect, with adhesion being enhanced at higher copolymer molecular weight. For other PBA/PMMA compositions, no reinforcement was seen, irrespective of molecular weight.