Pathogenesis intercellular communication system as called Quorum Sensing (QS) plays a crucial role in chemical communication between bacteria involving autoinducers, receptors and controls production of virulence factors in bacteria. A. hydrophila was reported to be regulated by QS pathways, indicating that it is involved in QS network regulation correlated with bacterial virulence. In A. hydrophila strains, it initiates disease process by preventing premature stimulation of immune system by critical gene expressions. A. hydrophila is fish pathogen which produces N-Acyl Homoserine Lactone (AHLs) QS signal molecules and possesses homologues of the model strain Vibrio fischeri luxI and luxR QS genes termed ahyI and ahyR, respectively. A. hydrophila secretes AHL signal molecule with LuxI and ahyI gene, and senses AHL signal molecule with LuxR and ahyR gene. In this work, 20 clinical A. hydrophila strains were analysed for presence of Quorum Sensing genes ahyI and ahyR by Polymerase Chain Reaction (PCR). The QS genes ahyI (78 bp) and ahyR (86 bp) were detected in a total of 20 strains. Thus, it has been proven that pathogen bacteria A. hydrophila possesses LuxI/LuxR-Type QS. This genomic analysis determined the comprehensive QS systems of A. hydrophila, which might provide novel treatment strategy regarding the mechanisms of virulence signatures correlated with QS. With identification of QS and all members of system (AHLs, AI, QSI e.g.), early diagnosis of disease is brought to agenda and it is expected to break new ground in diagnosis of fish diseases. As previously reported, these data add A. hydrophila to the world of bacteria now known to control gene expression through QS.