This practice establishes the apparatuses and materials needed, possible hazards, and two standard procedures for taking samples of cryogenic aerospace fluids for analysis. For the Dewar flask procedure, a clean Dewar flask is used to collect a sample of cryogenic aerospace fluid either from a sampling valve, or poured from a Dewar flask used for storage. Whereas, for the cryogenic sampler procedure, the sampler is used to withdraw a small amount of liquefied gas from a large supply, and is then allowed to cool until a steady stream of cryogenic liquid exists in the sampler. Once the sampling valves are closed, the trapped liquid will convert to gas and pressurize the sampling vessel.