This study aimed to determine the serotypic differences between Lactococcus garvieae strains isolated from rainbow trout obtained from different fish farms in Turkey. For this purpose, some phenotypic properties of isolates were determined and then ELISA test was performed to deter-mine serotypic differences. It was determined that all 22 L. garvieae isolates used in the study gave a cream colored, bright, rounded smooth S type colony in Triptic Soy Agar (TSA) and all strains were nonmobile in the native examination. Morphologically, all isolates were found to be Gram positive, nonmobile, α-hemolytic, to have a growth of 0-6.5% NaCl salinity, 21, 37 and 45℃ temperature, and to be oxidase and catalase negative. After examining the biochemical made with API Rapid ID 32 Strep test, it was observed that two L. garvieae isolates were different from the other isolates in terms of sucrose use and one L. garvieae isolate was different from other isolates in terms of maltose profile. According to the results of ELISA test used to determine the serotyp-ical differences of the isolates, two L. garvieae isolates were serotypically different from the other isolates and L. garvieae isolates used in the study formed two different serotypic groups.