A control system controls a hybrid vehicle having an engine for rotating a drive axle, an electric motor for assisting the engine in rotating the drive axle with electric energy and converting kinetic energy of the drive axle into electric energy, and an electric energy storage unit or a capacitor for supplying electric energy to the electric motor and storing electric energy outputted by the electric motor. When the remaining capacity CAPAremc of the capacitor is smaller than a first predetermined remaining capacity REMC1 or the remaining capacity CAPAremc of the capacitor is smaller than a second predetermined remaining capacity REMC2 (>REMC1) and an assistive-mode integrated discharged value DISCHG of the capacitor 14, which is calculated while the electric motor has operated in a latest mode to assist in running the hybrid vehicle, is greater than a predetermined discharged quantity disch1, the control system calculates a regenerated quantity increasing corrective coefficient Kregup (>1) depending on the vehicle speed. The control system multiplies a basic decelerating regenerative quantity DECreg by the corrective coefficient Kregup to determine a demand output power MOTORpower for the electric motor for thereby increasing the amount of electric energy regenerated by the electric motor when the hybrid vehicle decelerates.