Tracer technique is one of the most effective tracking and monitoring techniques, which has been applied in oil and gas production in the world such as interwell study and residual oil saturation determination. Chemical tracers were used instead of radioactive tracers due to their safety for the environment and health. Among them, perfluorocarbon compounds (PFCs) are potential ones for the gas-tracer technique in the tertiary recovery stage of oil production. In this report, we studied to establish the analytical procedure for 6 PFC compounds in gas samples from the oil reservoir using thermal desorption combined with gas chromatography-mass spectrometry and chemical ionization source (TD-NICI-GC/MS). Gas samples were taken into the Capillary Adsorption Tube (CAT) containing carboxen 569 for thermal desorption and analyzed on gas chromatography-mass spectrometry. The detection limit of this procedure was at fL/L (10-15 L/L) level. The method will be applied to determine the PFC content of gas samples from some of Vietnam’s oil reservoirs.