The disclosure concerns a mixing valve for mixing two coating agent components (e.g. master batch and hardener) to form a multi-component mixture, with two coating agent inlets for supplying the two coating agent components and with two coating agent valves for controlling the coating agent flow through the two coating agent inlets, as well as with a coating agent outlet for discharging the multi-component mixture in a specific outflow direction. The disclosure provides that at least one of the coating agent valves is formed as a rotary slide valve having two plane-parallel valve discs which are rotatable relative to each other about an axis of rotation.