A control system for an internal combustion engine equipped with a supercharger calculates a target intake mass airflow (mt′) in accordance with an accelerator pedal travel (θA), using a virtual internal combustion engine model having a virtual upstream intake air pressure (PA). The control system then calculates a target throttle opening (θ) in accordance with a measured upstream intake pressure (PIN) so as to provide the target intake mass airflow (mt′), and controls a throttle valve based on the target throttle opening (θ).