Gas chromatography and mass spectrometry are common tools in the food research and quality control laboratories. Gas chromatography has been applied in many areas, including the analysis of sugars, free fatty acids, lipids, oligosaccharides, amino acids, pesticides, polychlorinated biphenyls (PCBs), flavors, off-flavors, moisture content, and food packaging materials. Mass spectrometry has found application in virtually all of these same areas, since gas chromatography is not an identification tool but rather a separation/detection technique. All too often one sees someone who bases a judgment on a gas chromatographic peak for which the identity or purity is virtually unknown. Mass spectrometry is an unequaled identification tool which is very compatible with gas chromatography and has found additional application by being used as a specific detector for gas chromatography. When operated in the multiple ion monitoring mode, the mass spectrometer can function to selectively monitor individual compounds which are potentially unresolved by the gas chromatograph or may permit detection at concentrations below the gas chromatographic threshold. There is little question that gas chromatography and mass spectrometry go together and are supportive. The development of low-cost mass spectrometers has permitted this coupling in even the smaller food companies.