A hydrodynamic machine, in particular a hydrodynamic retarder, having a first revolving blade wheel (1); having a second blade wheel (2), likewise revolving or stationary; the two blade wheels (1, 2) form a working chamber (3) that is filled or can be filled with a working medium in order to transmit a torque hydrodynamically from the first blade wheel (1) to the second blade wheel (2); having a casing (4) which, together with one of the two blade wheels (2), encloses the other blade wheel (1) or both blade wheels (1, 2); having a drive shaft (5) in order to drive the first or the second blade wheel (1, 2) mechanically; the drive shaft (5) being sealed off with respect to the casing (4) by means of a sliding ring seal (6) in order to prevent any escape of working medium between the drive shaft (5) and the casing (4); the sliding ring seal (6) has a sealing liquid supply (7) in order to cool and/or to lubricate the sliding ring seal (6); characterized by the following features: the sliding ring seal (6) has a first sliding ring (8) and a second sliding ring (9) which are arranged to enclose one another concentrically in the radial direction and each have a sealing surface (10, 11), and which, together with a mating element, seal off a sealing gap running in the radial direction with respect to the drive shaft (5); a sealing liquid channel (12) opens into the sliding ring seal (6) in the radial direction between the two sealing surfaces (10, 11) in order to cool and/or to lubricate the two sealing surfaces (10, 11) with sealing liquid.