ESA and EMPRESARIOS AGRUPADOS have been developing EcosimPro since 1989. The initial objective was to provide powerful capabilities to handle the simulation of Environmental Control and Life Support Systems (ECLSS). Because of the multi-disciplinary nature of ECLSS (thermal, fluids, chemical reactions, electrical and control features), EcosimPro has been designed as a generic, flexible and modular tool. It is capable of solving a large set of Differential Algebraic Equations (DAEs) both for steady and transient states. The new EcosimPro 3.0 release (available on PC-Windows platform) uses the powerful concept of Object-Oriented Simulation Language, which enables the definition of components that can be re-used as libraries. The look and feel of EcosimPro is identical to Microsoft® software (tree browser for instance) and is very user-friendly. The User Interface has been designed to define and connect the system components either using the EcosimPro language (EL) or using a professional 2D CAD package (Smartsketch from Intergraph).This paper presents recent results obtained in the simulation of ECLSS and other systems (propulsion, fuel cells), as well as improvements and future capabilities.