This paper reports on an important discovery that is: hydrostatic actuation systems are able to manipulate heavy loads with sub-micron precision and large stroke. In this relation, the design of a high-precision hydrostatic actuation system referred to as the ElectroHydraulic Actuator (EHA) is presented. A laboratory prototype of this system has achieved an unprecedented level of performance by being able to move a large load of 20Kg with a precision of 50 nanometers and a stroke of 12cm. This level of performance places the hydrostatic actuation concept in competition with piezoelectric platforms in terms positional accuracy. Experimental results from this prototype are reported and analyzed.