A miniaturized multi-chip module suitable for application to wireless transmission devices includes a substrate, integrated circuit chips mounted on and connected electrically to the substrate, and an interposer mounted on one surface of the substrate. The interposer cooperates with the substrate to confine a receiving space for receiving the integrated circuit chips on the surface of the substrate to which the interposer is attached, and is provided with conductors that are connected electrically to the substrate. Therefore, when the interposer is mounted on a circuit board, the conductors serve as external electrical connections for the integrated circuit chips. A method for manufacturing the miniaturized multi-chip module is also disclosed.