A hydraulic system, especially in a high-pressure application, comprises a pressurized-fluid tank, a pressurized-fluid pump driven by a drive unit, at least one hydraulic load that can be pressurized thereby and a control and/or distribution unit connected fluidically between the pressurized-fluid pump and the load. This unit is provided with a housing and a core received therein and connected rigidly with the housing, which core bears with part of its surface in the region of a common, closed, especially cylindrical joint face with the housing on a corresponding inside face of a housing opening. Surface groove-like flow ducts are provided on the core and/or the housing in the region of the joint face, and the pressurized-fluid pump is directly built onto the control and/or distribution unit in the region of a free end face of the core.