In a vehicle control system, an opportunity for detecting abnormalities in an atmospheric pressure sensor using an intake pressure sensor of the engine is appropriately provided. A vehicle control system 10 includes an engine 12, rotating electric machines 14 and 16, a power supply circuit 18, an intake pressure sensor 20, an atmospheric pressure sensor 22, an IG-ON/OFF switch 70, and a control device 48. A control unit 50 of the control device 48 includes a system start/stop module 52 which starts and stops operation of the entire system, a sensor state determination module 54 which determines whether the atmospheric pressure sensor 22 is in an abnormal state based on a detection value of the intake pressure sensor 20, a boosting limit module 56 which limits the boosting voltage of the voltage converter 34 corresponding to a detection value of the atmospheric pressure sensor 22, and a power supply stop delaying module 58 which delays a stop of electric power supply from a low-voltage battery 44 for a predetermined period after the engine stopped.