Abstract: The invention relates to a process and an apparatus for the aseptic packaging of products such as foodstuffs and pharmaceutical products, using a tunnel over the filling track of the filling machine, which tunnel is provided with means for introducing sterile gas. This aseptic packaging could be improved by introducing the sterile gas only from one side, preferably such that the gas stream moves contrary to the product stream, and by providing means which ensure a horizontal gas flow of low turbulance in the tunnel so that the suction of ambient air into the system is avoided.