An internal-combustion engine has a plurality of cylinders each with two intake valves driven by respective pumping pistons operatively associated to cams of a camshaft, by respective hydraulic circuits. The hydraulic has its pressure chamber communicating with hydraulic actuators of the two intake valves, so that the two intake valves of each cylinder are controlled, via two different hydraulic circuits, by cams associated to two different cylinders. Each cam is configured to give rise to a cycle of opening and closing of each of the intake valves in an angular range of rotation of the crankshaft less than 180° such that, in each operating cycle of a cylinder, only the first intake valve initially opens and closes while the second intake valve remains closed, and then the second intake valve opens and closes while the first intake valve remains closed.