An exhaust gas recirculation system for an internal combustion engine employs a first control valve in an exhaust gas introduction passageway, a second control valve in an air conduit connecting the engine intake passage to atmosphere, and a regulating valve responsive to differential vacuum intensities for operating vacuum-responsive actuators for the control valves. A recirculation stop valve vents to atmosphere the actuator for the second control valve in response to an engine operating condition, to stop recirculation of exhaust gas.