A pumping unit for a machine to distribute concrete includes a pair of cylinders provided with a relative pumping piston movable linearly for a determinate travel to feed the concrete to a determinate circuit to distribute the concrete; and a hydraulic command circuit operatively connected to both the cylinders, to determine an alternate pumping movement of the relative pumping pistons. The pumping unit includes at least a sensor member operatively associated to at least one of the cylinders in order to detect point-by-point one or more data relating to the operating condition of the pumping piston during its movement for the whole travel. The data includes at least one of position, speed, stress and direction of movement of the relative piston.