The rotating union for two different fluids comprises a hollow shaft (2) mounted rotatably in a stationary housing (1), with two separate axial throughflow channels (4, 5). A slide ring packing assembly is provided between the hollow shaft (2) and two separate inlet channels (9, 17) provided in the housing (1) for the two fluids. This includes a common slide ring (8) which is connected at its face to the hollow shaft (2) and comprises a central bore (8a) and several axial passages (8b) arranged concentrically thereto, and in the housing (1) a central slide ring (11) and a slide ring (14) concentrically surrounding the latter. The concentric slide ring (14) comprises several axial passages (14a) which are arranged in a circle concentric to the axis of rotation (A) and connected to the inlet channel (17) for the second fluid. Between the outer circumference of the central slide ring (11) and the inner circumference of the concentric slide ring (14) is provided an annular chamber (18) extending as far as the sliding surface (8c) of the common slide ring (8) and communicating with an inlet channel (23) provided in the housing and an outlet channel (24).