Abstract: The present invention is a liquefaction process for atmospheric gases. In the process, one or more atmospheric gas streams (e.g., air, nitrogen, etc.) are compressed in a compression zone to provide both an intermediate stream and a high pressure stream. The high pressure stream is then cooled and at least a portion of it is expanded to provide refrigeration. The remaining high pressure stream is then further cooled and expanded whereby it is partially liquefied and separated into a vapor stream and a liquid atmospheric gas product stream. The intermediate pressure stream is cooled and at least a portion of it is expanded to provide refrigeration. The remaining intermediate pressure stream is further cooled and combined with the expanded portion of the high pressure stream and expanded to provide refrigeration. The discharge from this expansion, the vapor stream, and the discharge of the expansion of the portion of the intermediate pressure stream are warmed and recycled to the compression zone.