The modelling of pressures in silos has been attempted by numerous researchers using a variety of different methods. Starting with the work of Janssen, the slice element method, the method of characteristics, the finite element method and the method of granular dynamics are reviewed. Every model needs constitutive parameters which have to be found from experiments. A method to calibrate the more recent - and highly complex - constitutive models from general tests is presented. Besides the models for silo pressures, several models of flow in silos are considered.