The effect of NaCl concentration on the adhesion of Edwardsiella tarda to goldfish intestine was studied by the viable cell count. Three strains of E. tarda with different hemagglutinating activities (HA) for guinea pig erythrocytes were cultured in a peptone-yeast extract broth containing 3% NaCl (3%-NaCl culture) and without NaCl (0%-NaCl culture). Both of the 3%-NaCl cultures of the strains FK1051 and KG8401 displayed significantly higher adhesion than their respective 0%-NaCl cultures. On the contrary, no significant difference in adhesion was found between the 0%- and 3%-Nacl cultures of the strain SU166, with low adhesion in both. Scanning electron microscopy of the bacteria adhered to the intestine confirmed the results of the viable cell count. Similarly, the time-course study on E. tarda infection showed significant increases in the bacterial numbers recovered from the kidney of fish infected with bacteria grown in high NaCl concentration in case of FK1051 and KG8401 strains. The adhesion and time-course results were consistent with the previous data for HA and in vitro adherence of these strains. The effect of NaCl on phagocytosis of E. tarda was studied using murine macrophages, revealing increased internalization of the bacteria in the 3%-NaCl culture. However, the total pathogenicity of E. tarda was not obviously altered by the increase of NaCl in the culture medium.