Morphological and cytochemical characteristics of neutrophil in the oblong rockfish Sebastes oblongus were examined by light microscopy. Two types of granules, chromophobic granule (βG) and basophilic granule (γG) were observed in the neutrophil. The βG contained rod-shaped central core (RCC) which was stained purple with Giemsa and peroxidase (PO) negative. Surrounding part of RCC (substance of βG) was not stained with Romanowskytype stain and PO positive. The γG was stained light blue with May-Gr?nwald (MG) and MGGiemsa, but not stained with Giemsa.