The mild flavor, high protein content, and low cost of Basa fish (Pangasius bocourti) make it a popular food. However, Basa fillets are extremely perishable, which makes transportation and storage difficult, much like many other fish products. Lipid oxidation and microbial contamination are two major causes of fish fillet degeneration, which can result in serious financial losses as well as possible health hazards. Many preservation methods, such as cold storage, chemical preservatives, and irradiation, have been used for enhancing the shelf stability and hygienic quality of seafood. A common method for food preservation that effectively decreases the microbial load and increases shelf life is gamma irradiation., when combined with natural antimicrobial and antioxidant agents, like plant extracts, irradiation could further enhance preservation efficiency. Because lemongrass (Cymbopogon citratus) contains a lot of bioactive substances including flavonoids and citral, it is well-known for its antibacterial, antioxidant, and flavor-enhancing qualities. A potential method for enhancing the safety and quality of Basa fish fillets is to combine gamma irradiation with varying concentrations of lemongrass extracts. This study is to assess the efficiency of 4.5 kGy of gamma irradiation in conjunction with varying concentrations of lemon grass (2%, 4%, and 6%) for improving the hygienic quality and shelf stability of Basa fish (Pangasius bocourti) fillets during cold storage. The findings demonstrate that by suppressing bacterial development and preserving sensory qualities, the combination of 4.5 kGy gamma irradiation and lemongrass extract significantly increased preservation efficiency, especially at a 6% concentration. This study concludes that the combination of gamma irradiation by dose 4.5 kGy and lemongrass extract by 6% concentration is an effective preservation method for extending the safety and quality of Basa fish fillets during cold storage.