A numerical model is developed to evaluate droplet breakage and coalescence rates in a continuous oscillatory baffled reactor (OBR). The structure of the model is similar to that of the population balance approach, but concentrates on droplet interactions with simpler assumptions of a functional form for breakage and coalescence rate constants. The OBR is a relatively new reactor technology and offers enhanced and more uniform mixing than traditional reactors, making some model assumptions more closer to the reality. In this paper, we present the development, robustness and validation of the modelling process together with the predicted results for the OBR system.