Infectious Pancreatic Necrosis Virus (IPNV) is a viral agent that causes significant losses in salmonid fish in the rainbow trout and salmon farming sectors. The present study aimed to examine of quercetin effects on (IPNV) replication in Rainbow trout gonad (RTG-2) cell cultures. Half-maximal (50%) cytostatic concentration (CC 50) of quercetin were detected in the RTG-2 cell culture by cytotoxicity test with Cell Counting Kit-8 (CCK-8, Sigma-Aldrich) (n=3). Titration, cytopathogenic effect reduction, and qRT-PCR tests were used to determine the effect of quercetin on IPNV replication in RTG-2 cell culture. At the end of the cytotoxicity test, the non-toxic dose of quercetin was determined. Besides that, 50 μmol/L quercetin decreased the titer of IPNV in RTG-2 cells from 10-7 to 10-5, at the same time, the same dose of quercetin reduced the viral load to 40%. We concluded that quercetin is a potent antioxidant agent for IPNV infections and it can be an option in the treatment of the IPN disease.