Vibriosis is fish disease responsible for considerable economic hardship to mariculture operation worldwide. Vibrio anguillarum is an important infectious agent. The first step of infection requires attachment of the bacterium to the host. The flagellum has been suggested to be involved in virulence as a motility organelle that carries an adhesive component. The iron-uptake system of v. anguillarum is important to the pathogenic process. Extracellular compounds such as hemolysin and metalloprotease have been involved in virulence too. The article reviews all factors including exotoxin, adherence factors, invasion factors, cell surface components and iron-uptake system.