This chapter aims at discussing the content of multi-agent based simulation (MABS) applied to computational biology, i.e, to modelling and simulating biological systems by means of computational models, methodologies, and frameworks. In particular, the adoption of agent- based modelling (ABM) in the field of multicellular systems biology is explored, focussing on the challenging scenarios of developmental biology. After motivating why agent-based abstractions are critical in representing multicellular systems behaviour, MABS is discussed as the source of the most natural and appropriate mechanism for analysing the self-organising behaviour of systems of cells. As a case study, an application of MABS to the development of Drosophila Melanogaster is finally presented, which exploits the ALCHEMIST agent-based simulation platform.