A method of operating a UV disinfection device provided with at least one UV emitter, including supplying the emitter with an operating voltage for a firing and continuous operation thereof, modulating the operating voltage, an operating current, or an electrical power of the UV emitter, detecting the UV radiation emitted by the emitter with a UV sensor that is adapted to temporally resolve the modulation, evaluating the signal recorded by the UV sensor, and checking whether the modulation in the signal given off by the sensor corresponds to a desired value.