Well-defined acrylate RAFT polymers and multiblock-copolymers have been synthesized via the use of a continuous-flow microreactor, in which polymerizations could be executed in 520 min reaction time. First, Poly(n-butyl acrylate) (PnBuA) was synthesized in the micro-flowreactor by using two different trithiocarbonate RAFT agents. Reaction time and reaction temperature were optimized and collected samples were directly studied with NMR, SEC and ESI-MS to determine conversion, molar mass and end group fidelity. Using the continuous flow technique, highly reproducible and fast polymerizations yielded quantitatively functionalized PnBuA in a very facile and efficient manner. One batch of RAFT acrylate polymer with a molar mass of 1100 g mol1 and excellent end group fidelity was employed as a macro-RAFT agent for the subsequent copolymerization with different acrylate monomers (2-ethylhexyl acrylate, t-butyl acrylate, n-butyl acrylate). Using this procedure, a sequential multiblock-copolymer (Mn = 31,200 g mol1, PDI = 1.46) consisting of five consecutive acrylate blocks was synthesized. This study clearly demonstrates the potential of using a continuous-flow microreactor for subsequent RAFT polymerizations towards well-defined multiblock-copolymers. (c) 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013, 51, 2366-2374