A model for the formation of solid spneres from droplets of colloidal suspensions based on simultaneous heat and mass transfer considerations was presented. The model considers the particle formation process to be consisting of two stages. During the first stage, when a droplet is placed in a heated environment, evaporation takes place along the drop surface. As a result, the size of the droplet decreases and the concentration of the colloidal matters within the droplet increases until the surface concentration reaches a critical value and a solid crust is formed at the droplet surface. During the second stage, the crust gains in thickess due to continued evaporation and the transport process is similar to that of drying in a porous medium with moving boundaries. Numerical solutions for both stages were obtained and the results enable the prediction of the droplet weight and size histories. Based upon the experimental results collected on the formation of particles for droplets of aqueous albumin solution, the necessary procedure for model validation and parameter estimations was established.