In a process for the vaporization of liquefied gases, e.g., oxygen, argon, nitrogen, in a sufficiently small quantity to have been vaporized heretofore without use of the cold content therein, the improvement of vaporizing said liquefied gas in indirect heat exchange with a gaseous medium being a process gas, e.g., hydrogen, or fuel gas, e.g., natural gas, and using the resultant cooled gaseous medium for industrial or domestic purposes in either the gaseous or liquid form, e.g., reaction gas, inert environment, heating. The gaseous medium may be fractionally condensed simultaneously to remove impurities therefrom, e.g., moisture from technical grade hydrogen, or a heavy fraction from natural gas.