This paper describes a theoretical model to capture the rate of erosion of a silty sand based on the principle of conservation of energy. Erosion is considered to begin when the interparticle bonds between grains are broken by hydrodynamic stresses exerted on the soil particles. These detached particles are then suspended and transported by the flow of eroding fluid. It is further assumed that once the particles are fully suspended and have reached the flow velocity, resettlement does not take place. Stabilization of soil particles because of lignosulfonate (LS) treatment is represented by the increased strain energy required to break the interparticle bonds. The equation proposed in this study is based on the shear stress-strain characteristics, mean flow velocity, mean particle diameter, and the packing arrangement of particles. The result of the proposed study is presented in the form of erosion rate versus the hydraulic shear stress. The model is validated with a series of laboratory erosion tests using the Process Simulation Apparatus for Internal Crack Erosion (PSAICE) for different percentages of LS. The model results are in good agreement with the experimental observations. DOI: 10.1061/(ASCE)GT.1943-5606.0000766. (C) 2013 American Society of Civil Engineers.