Abstract. This paper describes DCaseLP, a multi-language development environment for Multi-Agent Systems. DCaseLP provides tools and languages for modelling and implementing a MAS prototype following a set of steps which guide the developer from the late requirement analysis to the prototype implementation. Full support for validating the MAS model by running the prototype in the JADE platform is offered. DCaseLP and its ancestor, CaseLP, have been employed to develop many applications also in collaboration with Italian companies, thus demonstrating the feasibility of the proposed approach.