Abstract: Provided in a gas-feed system, in particular a system for supplying methane or hydrogen to an internal-combustion engine, is an electronic pressure-reducer or pressure-regulator unit, integrated in which are both a pressure-reducing valve for reducing the pressure of the gas coming from the fuel tank to a value suitable for supplying a distribution manifold or rail and a modulating solenoid valve that functions as modulator of the degree of pressure reduction performed by the pressure-reducing valve. Likewise made in the body of said unit are passages that provide the communications of said valves with one another and of each of said valves with the inlet and the outlet for the gas in said unit. Furthermore, the unit incorporates an electronic control module for controlling the modulating solenoid valve.