We report a novel continuous-flow hydrothermal method for the synthesis of layered double hydroxide (LDH) nanoplates. The precursor solutions may be fed to the reactor so that the production of LDHs occurs in a continuous mode. By control of the synthesis temperature, pressure and contact time, the synthesis of LDH nanoplates can be tuned with constant and consistent product quality. This very general and simple approach shows high potential for commercial scale-up.