Physics validation of detector simulation tools for LHC

Extensive studies aimed at validating the physics processes built into the detector simulation tools Geant4 and Fluka are in progress within all Large Hadron Collider (LHC) experiments, within the collaborations developing these tools, and within the LHC Computing Grid (LCG) Simulation Physics Validation Project, which has become the primary forum for these activities. This work includes detailed comparisons with test beam data, as well as benchmark studies of simple geometries and materials with single incident particles of various energies for which experimental data is available. We give an overview of these validation activities with emphasis on the latest results.