From origins in economics and financial analysis, microsimulation has become an important technique for spatial analysis. The method relies on conversion of aggregate census tables, sometimes complemented by sample data at the individual level, to synthetic lists of people and households. The individual records generated by the microsimulation can be aggregated flexibly to small areas, linked to create new attributes, and projected forward in time under stable conditions, or in the context of ‘what-if’ policy scenarios. The chapter outlines the basic building blocks of microsimulation and shows how these are combined within a representative practical application. It is argued that further progress can be expected through advances in computation, assimilation of data into models, and greater capacity to handle uncertainty and dynamics. We also expect the creation of more sophisticated architectures to reflect the interdependence between population structures at the micro-scale, and the supply-side infrastructures and urban environments in which they evolve.