Abstract: A connection coupling which can be coupled or connected under pressure and employed with hydraulic lines, comprising a non-pressure loaded coupling half and a coupling half under pressure, in each coupling half there is centrally mounted a valve guide. In each valve guide there is axially displaceably arranged a spring-loaded hydraulically impingeable or loadable valve in such a manner that the valve heads, during the coupling operation, are pressed against one another. The non-pressure impinged valve is shifted through twice the possible valve stroke of the pressure impinged valve, and the non-pressure impinged valve is loaded with a spring which is stronger than the spring loading the pressure impinged valve, so that upon pressure equalization the previously pressure impinged valve is pressed in its open position against a stop provided at the previously pressure impinged coupling half, there being provided a maximum valve-passage cross-section for both valves.