Shrimp are highly valued crustaceans with high commercial demand since they are rich in nutrients and have an appealing taste with low saturated lipid. Nevertheless, they are perishable and can undergo rapid quality deterioration during postharvest handling, processing, and storage. Melanosis is one of critical undesirable quality deterioration associated with discoloration or blackening triggered by indigenous polyphenol oxidase or tyrosinase. Although this phenomenon does not harm the consumers, it can negatively impact on customer acceptability. In some shrimp species, indigenous proteases can induce textural changes, particularly texture softening due to the drastic degradation of muscle proteins as well as connective tissue. The small peptides can serve as the nutrients for microorganisms, thus favoring the proliferation of spoilage microorganisms. In addition, oxidation of lipid and protein can also contribute significantly to quality deterioration related with the off-odor or development of aggregated proteins with poor functional property. This chapter covers various factors affecting shrimp’s postharvest quality losses. The role of biogenic amines and indole in relation to spoilage and the importance of monitoring spoilage indicators to ascertain shrimp’s quality were discussed. Additionally, the chapter provides several traditional and innovative approaches to mitigate melanosis and prevent or retard quality deterioration in shrimp. Several preservation methods have been explored, involving the uses of chemical preservatives, natural additives, and nonthermal processing technologies. Novel nonthermal technologies including high-pressure processing, cold atmospheric plasma, pulsed electric field, active and modified atmosphere packaging technologies, etc. have been addressed for shrimp preservation.