This paper reviews the use of discrete particle models (DPMs) for the study of the flow phenomena prevailing in fluidized beds. DPMs describe the gas-phase as a continuum, whereas each of the individual particles is treated as a discrete entity. The DPMs accounts for the gas-particle and particle-particle interactions. This model is part of a multi-level modeling approach and has proven to be very useful to generate closure information required in more coarse-grained models. In this paper, a basic DPM, based on both the hard- and soft-sphere approaches is described. The importance of the closures for particle-particle and gas-particle interaction is demonstrated with several illustrative examples. Finally, an outlook for the use of DPMs for the investigation of various chemical engineering problems in the area of fluidization is given. (c) 2006 Elsevier Ltd. All rights reserved.