The invention relates to a method of controlling the exposure of an X-ray image. Starting values for the tube current, the tube voltage and the exposure duration are hereby set on the X-ray tube (10). Following the start of the exposure, the resultant dose rate is measured by a sensor (30, 31) and made available to a control system (100, 200, 300). In order to achieve a predetermined dose for the X-ray image, the control system adjusts the following variables in succession: the tube current within a current range; if applicable, the exposure duration within a time slot; the tube voltage within a voltage range; the exposure duration within the time slot. A rapid controlling of the tube current is enabled, preferably by the pulse-width modulation of the counter-voltage at the control grid of the X-ray tube.