Abstract: Vibrio anguillarum O1 was isolated from diseased cultured rainbow trout Onchorhynchus mykiss, in the Southern Aegean of Turkey with lesions and signs of vibriosis. Gram (-), motile and curved rods from diseased rainbow trout were identified after physiological, biochemical and slide agglutination tests as V. anguillarum O1. Koch postulates were fulfilled with the isolated bacteria. The antibiotic susceptible test results showed that V. anguillarum strains were susceptibility to amoxycillin, ampycilline, flumequin, furazolidone, kanamycin, potentiated sulphonamide and oxolinic acid.