Purpose: We investigated antibacterial activities of quercetin and trans-chalcone against contact lens-related bacteria and evaluated their potential as disinfectant in contact lens multipurpose solution(MPS). Methods: Antibacterial activities of quercetin and trans-chalcone, which are flavonoids, against Staphyloccus aereus and Pseudomonas aeruginosa were determined. After trans-chalcone treatment in MPS with weak antibacterial activity, its growth inhibition effect to bacteria was also determined. Results: Both of quercetin and trans-chalcone showed antibacterial activity against S. aereus, but did not show against P. aeruginosa. As the results of MIC against S. aereus, trans-chalcone showed higher activity than quercetin (quercetin: IC 90 149 µg/ml, IC 50 31.0 µg/ml trans-chalcone: IC 90 15.2 µg/ml, IC 50 8.9 µg/ml). In the antibacterial activities experiment of MPSs, MPS of F Company showed a low activity against both S. aereus and P. aeruginosa. The antibacterial activity of the F company's MPS was investigated by adding trans-chalcone. As a result, the antibacterial activity was exhibited from 75% concentration of IC 90 (11.4 µg/ml). Conclusions: Quercetin and transchalcone, which are flavonoids, showed antibacterial activities against S. aereus and trans-chalcone had higher activity. Hence, this result suggests that quercetin and trans-chalcone can be applied to a disinfectant of MPS.