The aim of this work was to investigate the effect of wetting parameters such as binder surface tension and liquid-solid contact angle, on fluidized-bed coating and agglomeration of solid particles. The effect of particle size on coating criteria was also studied. The coating support was spherical glass beads and aqueous solutions containing lactose monohydrate used as coating liquid. The results showed that both growth rate and efficiency increase with decreasing the particle size. In addition, a mathematical model based on the population balance concept, taking into account the simultaneous growth by layering and agglomeration was established to predict the time evolution of the particle size distribution. The comparison between experimental and calculated data permitted us to establish a law for the dependency of agglomeration kernel on wetting parameters.