The invention relates to a hydrodynamic machine, especially a hydrodynamic retarder, comprising two blade wheels which are opposite of one another in such a way that they jointly form a toroidal working chamber which can be filled with a working medium in order to hydrodynamically transfer torque by means of a cycle flow of the working medium in the working chamber from the first blade wheel to the second blade wheel, with the first blade wheel rotating about a rotation axis and the second blade wheel rotating about the same rotation axis in the same direction of rotation or opposite of the direction of rotation of the first blade wheel, or being held in a stationary manner. The invention is characterized in that at least one of the two blade wheels is subdivided in the region of its blades into at least two concentric rings.