CMS Fast Simulation: A tool for physics searches at the LHC

The CMS collaboration has developed a fast Monte Carlo simulation of the CMS detector with event production rates ~100 times faster than the GEANT4-based simulation, with comparable accuracy for most of the high level observables to be used in the physics analyses. We discuss basic technical principles of the CMS Fast Simulation and their implementation in the different components of the detector: the silicon tracker, the electromagnetic calorimeter, the hadronic calorimeter, the muon system, the Level 1 and the High Level Trigger. Comparison of the Fast Simulation results both with the GEANT4-based Full Simulation and with the LHC data will be shown.