Caetano, ArturSilva, António RitoTribolet, José2017-08-282017-08-282010The functional decomposition of a business process breaks it down into progressively less granular activities. Decomposition contributes to the modular design of a system, the reuse of its parts and to its overall comprehensibility. But achieving these qualities requires a business process to be decomposed consistently, which implies it is always split into an identical set of activities according to a specific purpose, regardless of the modeller’s and modelling context. This paper describes an application of the principle of role-based separation of concerns to consistently decompose a business process into its constituent atomic activities, thus separating its distinct features and minimising behaviour overlap. An activity is abstracted as a collaboration between role types that are played by entities. The decomposition method successively separates the overlapping roles until an activity is specified as a collaboration of an orthogonal set of role types. The method facilitates the consistent decomposition of a business process and the identification of its atomic activities. The relevance of the method is assessed through a number of scenarios according to the guidelines of design science research.enText/Journal Article10.18417/emisa.5.1.31866-3621