A vacuum patient positioning cushion includes an integrated rigid or semi-rigid positioning element located within a gas-impermeable outer cover, making it possible to easily and correctly position a patient for a radiation therapy or other procedure without the need or use of external positioning devices. The gas-impermeable outer covering defines an airtight enclosure having a valve stem and closeable vacuum control valve in selective fluid communication with the enclosure. The enclosure houses a filler material and a rigid or semi-rigid positioning element. A method of positioning a patient using the vacuum patient positioning cushion is also provided.