Simulation models for the prediction of pharmacokinetics in humans and other mammalian species, which are based on the physiology and mechanistic models of absorption, distribution, metabolism and elimination are reviewed. The structure of such models is explained with reference to papers describing the mathematical details and alternative representations of organ flow and distribution. Approaches to the modelling of more complex tissues such as tumours and the liver are also reviewed as well as some specific transport processes such as biliary secretion and methods of ADME property estimation by experimental and in silico models. Specific approaches to the modelling of gastro-intestinal transit are explained as is the extension of the approach to simulating drug-drug interactions following co-administration of more than one drug.