Context: One strategy to address the emergence of infectious diseases supported by the increasing cases of microbial antibiotic resistance is the development of anti-pathogenic drugs, a quorum quenching compound(s) capable of inhibiting microbial communication (quorum sensing inhibitor). Pseudomonas aeruginosa is one of the most common source of chronic opportunistic infections, which demonstrates the most consistent resistance to antimicrobial agents. Quorum sensing (QS) controls secretion of virulence factors in P. aeruginosa. Aim: This study aims to discover quorum sensing inhibitors (QSI) from some Indonesian medicinal plants ethanol extract to analyze their inhibitory activities against QS-mediated virulence factors in P. aeruginosa. Settings and Design: In-vitro experimental study-laboratory setting Material and Methods: Indonesian medicinal plant ethanolic extracts were tested for their capability to inhibit P. aeruginosa motility, biofilm formation using microtiter plate method, pyocyanin and LasA production using LasA staphylolytic assay. Statistical analysis used: Statistical significance of the data were determined using one way ANOVA, followed by Dunnett’s test. Differences were considered significant with P values of 0.05 or less. Results: Ethanolic extract of T. catappa leaves and A. alitilis flower capable to inhibit P. aeruginosa motility as well as pyocyanin production and biofilm formation. Both extracts also showed capability in reducing LasA protease production. Conclusion: T. catappa and A. alitilis are an interesting sources of innovative plant derived quorum quenching compound(s), thus can be used in the development of new antipathogenic drug.