This chapter highlights some of the molecular techniques and genes involved in safety, quality, and authenticity of fish and fishery products. The general trend in food safety is a shift from time-consuming culture-based methods to rapid molecular methods. For pathogens that are difficult to culture and for viral pathogens, molecular methods are key in assessing the safety of the fishery products. Hyperspectral imaging is essentially an artificial eye that builds on the visual inspection of fish. Nuclear magnetic resonance spectroscopy can be used to assess the fatty acid quality in whole fish, and to monitor qualitative and quantitative changes in fishery by-products. As in food safety testing, the trend in authentication is to use DNA-based techniques. DNA-based methods are increasingly preferred in both safety and authenticity assessment of fish and fishery products. Integrity as applied in the context of food chains covers not only the safety and quality of food products but also their authenticity and traceability.