ABSTRAK Aeromonas hydrophila dapat menginfeksi ikan dan manusia serta menunjukkan beberapa faktor virulensi yang dianggap berbahaya bagi kesehatan manusia. Pembentukan biofilm oleh bakteri A. hydrophila menjadi masalah utama dalam penanganan penyakit, karena menimbulkan kerugian yang mencapai hampir 100%. Ekstrak etanol daun kelor (Moringa oleifera Lam.) diduga berpotensi sebagai antibiofilm karena dapat menghambat proses pembentukan biofilm melalui gangguan Quorum Sensing (QS). Tujuan dari penelitian ini adalah untuk mengetahui potensi ekstrak etanol daun kelor (Moringa oleifera Lam.) dalam menghambat pembentukan biofilm A. hydrophila secara in vitro. Penelitian ini dilakukan dengan penambahan ekstrak etanol daun kelor dengan konsentrasi 2%, 4%, 8%, 10%, dan 12% terhadap penghambatan pembentukan biofilm bakteri A. hydrophila. Hasil penelitian ini menunjukkan bahwa ekstrak etanol daun kelor pada konsentrasi 12% memiliki potensi sebagai antibiofilm dengan persentase hambat biofilm sebesar 62,51%, namun masih belum se-efektif H2O2 3%. Kata kunci: Aeromonas hydrophila, biofilm, daun kelor, Moringa oleifera Lam. ABSTRACT Aeromonas hydrophila can infect fish and humans due to their several virulence factors that are considered harmful to human health. The formation of biofilms by A. hydrophila generates a major problem in the handling of diseases, because it involves death reaching almost 100%. Ethanolic extracts of drumstick tree (Moringa oleifera Lam.) leaves presumably have potency as antibiofilm that can inhibit the process of biofilms formation through Quorum Sensing (QS) disturbance. The aim of this study was to determine the potential of ethanolic extract of drumstick tree leaves to inhibit the formation of A. hydrophila biofilms in vitro. This research was conducted by adding ethanolic extracts of drumstick tree leaves with a concentration of 2%, 4%, 8%, 10%, and 12% to inhibit the formation of A. hydrophila bacterial biofilms. The results of this study showed that the ethanolic extract of drumstick tree leaves at a concentration of 12% had the potential as an antibiofilm with a percentage of biofilm inhibition of 62,51%, but it was still not as effective as H2O2 3%. Keywords: Aeromonas hydrophila, biofilm, drumstick tree leaves, Moringa oleifera Lam.