Abstract: A control device for hydraulic machines with variable displacement comprises a spring-biased control valve member for actuation of hydraulic adjustment means to provide the displacement variation, said valve member being engaged by one end of a double-armed lever on which acts a force proportional to the working pressure of the machine on an arm length relative to a pivot for said lever, which length is variable through a sliding movement of said pivot, and a means for controlling the maximum pressure of the machine. By a pressure means, the slidably movable pivot is resiliently biased against an indicating member responsive to the momentary adjusted displacement of the machine. Moreover, the control means for the maximum pressure of the machine consists of a stationary but adjustable abutment means adapted to restrict the length of the sliding movement of said pivot in order to determine a desired minimum value of said lever arm length and thus the value of the maximum pressure of the machine.