Continuous-flow atom transfer radical polymerization of 2-(dimethylamino)ethyl methacrylate in tubular microreactors of different diameters and geometries is studied. Scale-up of tubular reactors from micro (876μm ID) to milliscales (1753 and 4083μm IDs) is investigated. Coil flow inverter (CFI) reactors having 3 and 6m length (three and seven bends, respectively) are also considered for this study. Positive effects of flow inversion are visible in all three types of reactors expressed by an increase in molecular weight and monomer conversion as well as a decrease in the PDI for the same operating parameters. An increase in reactor diameter results in an increase in the throughput. It is worthy to mention that a CFI reactor having 4083μm ID and 3m (three bends) is found to increase the throughput by ten times without significantly increasing the PDI compared to a coiled tube microreactor with 876μm ID, 6m and no flow inversion pattern. However, pressure drops are higher (+0.1 bar) in case of larger diameter tubes. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.