The invention is directed to a system for supplying an internal combustion engine with fuel which includes the following functional components: a tank; a fuel pump; a metering device for metering fuel to the intake air; a feed line for conducting fuel from the fuel pump to the metering device; a reservoir which is so configured and mounted that fuel can be pumped therefrom to the metering device and which is not filled when tanking the tank and which can be again filled from the tank; and a control unit for driving the fuel pump and the metering device. The fuel pump is fixedly connected to the reservoir so that only fuel is pumped therefrom and a reservoir fill pump is provided which continuously maintains the reservoir filled as long as fuel is present in the tank. The system affords the advantage that even when, after tanking, fuel of a composition is present in the tank which is substantially different from the composition of the fuel present in the tank before tanking, the metering device first is supplied with fuel of the old composition and then the composition of the metered fuel only changes slowly. In this way, a continuous stable operation of the internal combustion engine is provided.