The rapid spoilage of Pacific white shrimp poses significant challenges in maintaining quality during storage and transportation. This study evaluated the efficacy of Kiam wood extract (KWE), recognized for its antimicrobial properties and high antioxidant activity, as a natural preservative to extend the shelf life of shrimp. Headless and deveined shrimp samples were artificially inoculated with Shewanella sp., a common spoilage bacterium, and treated with KWE at varying concentrations (0%, 0.2%, 0.4%, and 0.6%). The treated shrimp were stored at 4°C for 9 days, during which the abundance of Shewanella sp., lipid oxidation (measured by thiobarbituric acid reactive substances [TBARs]), pH, protein degradation (total volatile base nitrogen [TVB-N]; trimethylamine nitrogen [TMA-N]), and fatty acid stability were monitored. The results revealed that shrimp treated with KWE exhibited significant reductions in spoilage markers compared to the control groups. The proportion of Shewanella sp. in KWE-treated shrimp was over 20 times lower than that in untreated controls. Furthermore, KWE treatment significantly inhibited protein and lipid degradation, as indicated by reduced levels of TMA-N, TVB-N, and TBARs, while maintaining a more stable pH throughout storage. Notably, a KWE concentration of 0.6% demonstrated the highest efficacy in stabilizing key fatty acids, thereby preserving the nutritional quality of Pacific white shrimp throughout refrigerated storage. These findings highlight the potential of KWE as a natural and sustainable preservative for improving the storage stability of Pacific white shrimp, offering a viable alternative to synthetic additives in the seafood industry. PRACTICAL APPLICATION: Kiam wood extract (KWE) helps extend the freshness of shrimp by reducing spoilage bacteria and slowing the breakdown of proteins and fats. Even at a low concentration of 0.2%, KWE improves shrimp quality, with the best results observed at 0.6%. Seafood processors can use KWE as a natural alternative to synthetic preservatives, offering a cleaner label and higher-quality shrimp.