Abstract: The invention concerns a process respectively a device for filling a high pressure gas container (1), comprising the following steps: Supplying a liquefied or solidified first gas (2) into a gas container (1) while the gas container (1) is being cooled; stopping the cooling of the gas container (1) after the supplying step of the first gas; then introducing a gaseous second gas (3) into the gas container (1) and closing the gas container (1). The invention allows for a efficient, reproducible, reliable and economical filling of high pressure gas containers (1), in particular for airbag systems or for fuel cells, and allows to use conventional devices for introducing gases respectively closing gas containers that are not particularly adapted for low temperature respectively high pressure applications.