Abstract: A control system for an internal combustion engine comprises an ECU which calculates an amount of fuel to be supplied to the engine and determines a direct supply ratio and a carry-off ratio, based on operating conditions of the engine. The direct supply ratio is a ratio of a fuel amount directly drawn into the engine in a predetermined operating cycle of the engine to the whole fuel amount injected in the same operating cycle, and the carry-off ratio is a ratio of a fuel amount carried off the inner surface of the intake pipe and drawn into the engine in the predetermined operating cycle to the whole fuel amount which adhered to the inner surface of the intake pipe in an operating cycle immediately preceding the predetermined operating cycle.