The invention relates to a drive system for a hydraulic press. The drive system is of the type of secondary controlled system maintaining an impressed pressure of substantially constant magnitude in a pressure system. A hydraulic transformer comprises a pair of mechanically coupled hydrostatic machines each having a variably capacity. The first machine is connected to the pressure system and the second machine to the press cylinder. The invention provides a drive system in which biasing the press cylinder, rapid tranverse and pressing stroke, decompressing the fluid and flushing of hot fluid is accomplished in a closed loop free of throttling losses. The hydraulic transformer further allows to recover energy to the pressure system.