Abstract: Apparatus, and an associated method, for radio receiver circuitry operable in multi-modes to receive signals generated during operation of a multiple number of radio communication systems. The receiver circuitry is divided into receive chain portions which are selectably utilized depending upon which of the multiple number of the radio communication systems in which communications are to be effectuated. Selected combinations of the receive chain portions are formed, depending upon which of the modes in which the receiver circuitry is to be operable. Different combinations of the receive chain portions permit sharing of receive chain portions thereby to reduce the required number of circuit elements to form the multi-mode receiver circuitry. In one implementation, the radio receiver circuitry forms the receive portion of a dual-band, tri-mode mobile station operable in a selected one of three different cellular communication systems.