Based on two intuitions – (i) event-driven systems and multi-agent systems are two computational paradigms that are amenable of a coherent interpretation within a unique conceptual framework; (ii) integrating the two simulation approaches can lead to a more expressive and powerful simulation framework – we propose a computational model integrating Discrete-Event Simulation (DES) and Multi-Agent Based Simulation (MABS), based on an extension of the Gillespie’s stochastic simulation algorithm.