Thirty-one strains of Vibrio anguillarum serogroup O1 isolated in Italy and Greece from dead fish were subjected to rRNA gene restriction pattern analysis. With HindIII as the restriction enzyme, two different ribotypes were detected, of which one profile was dominant. One profile was found in all strains except one isolated from sea bass, sea bream, and mullet, while the second profile was found in all three strains isolated from rainbow trout and in one strain from a sea bass. With EcoRI only one profile was found.