Morphological characteristics of leukocytes (lymphocyte, monocyte and eosinophil) excluding neutrophil from Japanese lates (Lates japonicus) peripheral blood were examined using multiple Romanowsky-type stain (May-Grünwald (MG), Giemsa and MG-Giemsa) valuation. Lymphocyte had round to lobule-shaped nucleus with coarse chromatin-mesh. The cytoplasm contained some basophilic granules (lymphocyte basophilic granules, LBG). Monocyte had round to kidney-shaped nucleus with fine chromatin-mesh and the monocyte major granule (MMG) in the cytoplasm. Eosinophil had round to lobule-shaped nucleus and three types of granules, eosinophilic granule (EG), basophilic granule (BG) and azurophilic granule (AG) in the cytoplasm. The EG was stained orange with MG but not with Giemsa and MG-Giemsa. The BG showed light blue with all Romanowsky-type stain. The AG showed reddish purple with Giemsa and MG-Giemsa or colorless with MG. The color tone of AG may be due to the metachromatic reaction by azure B in Giemsa (metaazurophilic). Cytochemical characteristics of these leukocytes were also examined.