This paper presents a stochastic method to solve the population balance describing fluidized bed spray agglomeration. It dynamically develops a discrete sample of particles, presenting the entire solid holdup, under the influence of micro processes such as droplet addition, pre-drying and deposition on the particles. Special emphasis is put on the addition of liquid to the process, as well as on the micro process of droplet pre-drying. Pre-drying can occur during the flight of droplets from the tip of the nozzle to the fluidized bed, especially in top-spray configuration.