For the first time, the scale-up of oscillatory helical baffled reactors (OHBR) was studied. Residence time distributions were used to assess the scale-up over a wide range of net flow Reynolds numbers and oscillation conditions. A simple scale-up correlation based on oscillation and net flow conditions was established to predict the plug flow behavior at various reactor scales. It is suggested that operating conditions can be easily extrapolated from the laboratory scale to the pilot scale, and even to industrial scales, as the mixing behavior is similar.