This paper provides an overview of, and guidance as to when, why and how to choose and use, different simulation modelling methods as applied to healthcare. What simulation is and why it is necessary in addressing healthcare problems are discussed. In addition, key criteria for choosing an appropriate method (project type, population resolution, interactivity, treatment of time and space, resource constraints, autonomy and how knowledge is embedded) are covered. Key concepts for each method, moving from the simplest to most complex methods, are reviewed in some detail.