Abstract: Mounting for a rotary anode in an x-ray tube. A radially outer rotor sleeve, constituting the rotor of an electric motor, has an anode disc connected centrally thereof. A radially inner, supporting sleeve is telescoped within the rotor sleeve and is spaced radially therefrom. A central shaft extending longitudinally of the rotor sleeve and a further sleeve intermediate between the radially inner and outer sleeves has an anti-friction bearing with inner and outer races mounted on its respective ends, the inner race of each bearing being connected to the shaft and the outer race of each bearing being connected to the intermediate sleeve which is disposed coaxially of the rotor sleeve, the intermediate sleeve, and the shaft, and between and spaced from the shaft and the supporting sleeve. The intermediate sleeve is prevented from axial movement with respect to the supporting sleeve.