An experimental validation of a 3D kinetic, Monte Carlo model for simulation of microstructural evolution during solid state sintering will be presented. The model – a statistical mechanical model, which can simulate curvature-driven grain growth, pore migration, and vacancy formation, diffusion and annihilation – is validated by comparing microstructural evolution obtained experimentally for a copper powder compact. The 3D microstructural evolution of copper powder particles sintering was imaged in-situ by microtomography. The images show particles with internal porosity percolating through the particles. Microstructural features – e.g., neck formation and growth – from the experimental images as well as the overall densification rates are compared to the simulations.