Phagocytic activity of the pronephric and peripheral blood neutrophils was studied in the eel, Anguilla japonica, injected with physiological saline or bacterial cells. In phagocytosis, i.e. phago cytic rate and phagocytic index, and chemiluminescent response, the neutrophils from the bacteria injected eel showed higher activity than those from the saline-injected eel, and the peripheral blood neutrophils were more active than the pronephric ones. It is concluded that in response to the bacterial stimulus, the hematopoietic tissues of the kidney supply neutrophils with higher phagocytic activity to the peripheral blood.