Contacting of gas-liquid jets with particles/catalyst is essential in many fluidization processes. This paper discusses a momentum conservation model to determine the entrainment rate of solids and gas into a gas-liquid jet, injected in a fluidized bed. A novel experimental technique developed by Felli (2002) is used to verify the model results. Correction factors to the initial momentum calculated from the homogenous model are addressed. The model predictions are in good agreement with the experimental data. The present model can be used to characterize the behaviour of gas-liquid jets (fine sprays) injected into fluidized beds of fine particles.