The histopathology of Lactococcus garvieae induced streptococcosis in rainbow trout were characterized. Diseased fish showed bilateral exophthalmia, dark discoloration, distended abdomen caused by an accumulation of clear fluid in the stomach and intestines, and diffuse haemorrhage at the base of fins. Histopathological examination revealed lesions in the liver, kidney, spleen, gills and stomach. The liver was congested and microvesicular changes increased in hepatocytes. Necrosis and haemorrhage were observed in the kidney and spleen.