The version 3.0 of the DELPHES fast-simulation is presented. Its goal is the simulation of a multipurpose detector that includes a track propagation system embedded in a magnetic field, electromagnetic and hadron calorimeters, and a muon identification system. Physics objects that can be used for data analysis are then reconstructed from the simulated detector response. These include tracks and calorimeter deposits and high level objects such as isolated electrons, jets, taus, and missing energy. The new modular design makes it easy to adapt the simulation and reconstruction sequence to particular needs. New features such as a more advanced jets and missing energy reconstruction approach, crucial in the first years of the LHC, and pile-up simulation and mitigation, which will be needed for the simulation of the LHC detectors in the near future, have also been implemented.