A comparative histopathological study was made on natural infections of Edwardsiella tarda in Japanese flounder; Paralichthys olivaceus, red sea bream; Pagrus major, tilapia; Tilapia nilotica and Japanese eel; Anguilla japonica, and of Edwardsiella ictaluri in channel catfish; Ictalurus punctatus. Histopathological aspects of E. tarda infection of Japanese flounder and Japanese eel, and E. ictaluri infection of channel catfish were commonly characterized by suppurative inflammation in the infected lesions. Histopathological aspects of E. tarda infection of tilapia and red sea bream were commonly characterized by granulomatous inflammation preceded by macrophage infiltration in the infected lesions. As to inflammatory cells, causative bacteria overcame phagocytotic activities of neutraphils and macrophages resulting in intracellular multiplication. However, the number of bacteria was obviously decreased in the granulomas.