A computational model is developed to simulate evaporative spray injection into a hot gassolid fluidized bed. Eulerian treatment of three phases (gas, droplets, and particles) is used, with a population balance model to account for variation in agglomerate sizes. Submodels account for the interaction between droplets and hot particles, including momentum exchange, heat and mass transfer, and vaporization of injected liquid as droplets or liquid film on the surface of agglomerates. An energy approach is utilized to assess the outcome of collisions between particles, ranging from rebound to agglomeration and breakage. Model predictions agree well with experimental data in terms of the amount of liquid vaporized. The effects of superficial gas velocity and bed temperature are compared to experimental data, leading to reasonable agreement for the mass distribution of agglomerates, but some overprediction for small agglomerates. The new model can be utilized for in-depth investigation of liquid injection into hot gassolid fluidized beds with various operating conditions.