This research aimed to know the shelf life of mullet fillet with basil leaves extract treatment in different concentrations based on the number of bacteria contained on mullet fillet during low-temperature storage. The method used in this research was experimental with four treatments in double measurements. Mullet fillets were soaked for a half-hour in different concentrations of Basil leaves extract (0%, 1,5%, 3%, and 4,5%) and stored at low temperature (5-10℃). The parameters observed in this research were the number of bacteria, pH measurements, and weight loss. Based on the results of this study it can be concluded that the use of basil leaves extract with a concentration of 3% in mullet fillet during low-temperature storage has the longest shelf life of 11 days with the amount bacteria of 4.55 x cfu/g, pH value of 6.55 and weight loss value of 20,00%.