Morphological and cytochemical characteristics of neutrophil in the northern pike, Exos lucius were examined by light microscopy and the composition of neutrophil granule were inferred in this study. The neutrophils were round or oval, and the nucleus round to three lobule-shaped. The neutrophil possessed the chromophobic granule (βG) and Y-body. The βG was acid phosphatase and peroxidase positive. The Y-body was toluidine blue positive.