Droplet and particle-size distribution of inverse phase suspension polymerization of acrylamide was studied in an oscillatory baffled reactor (OBR). A discretized population balance model developed estimates the coalescence droplet rate and the type of droplet interactions contributing to the coalescence process in the system. In an OBR, fluid mixing is achieved by eddies generated when a set of prespecified orifice baffles moves periodically through liquid. These vortices can be controlled by a combination of geometrical and operational parameters, such as orifice diameter, baffle spacing, oscillation frequency, and oscillation amplitude. This type of mixing, combining with a closeto-constant level of turbulence intensity in the reactor, has led to a high degree of controllability and repeatability for both droplet and particle size, and a fine particle level significantly lower than a conventional stirred-tank reactor. Generic correlation is established linking the final bead size and Sauter mean droplet size with power dissipation.