A fuel metering control system for an internal combustion engine having a plurality of cylinders. The system includes an air/fuel ratio sensor and engine operating condition detecting device for detecting engine operating conditions at least including engine speed and engine load. The basic quantity of fuel injection is determined by retrieving mapped data predetermined based on an effective opening area of a throttle valve, according to the engine speed and engine load. An adaptive controller is provided to calculate a feedback correction coefficient to correct the quantity of basic fuel injection such that the detected air/fuel ratio is brought to a desired value. The output quantity of fuel injection is further corrected by fuel adhered on an intake manifold wall.