This experiment was performed to study the structure of esophageal mucousa and the histochemical properties of glycosaminoglycans of esophageal mucous cells in four teleostean species, i.e., Agramus agramus, Inimicus japonicus, Epinephelus chlorostigma and Helicolenus dactylopterus. To observe the structure of eosphageal mucosa, hematoxylin-eosin(H-E) staining was used. The glycosaminoglycans was stained with PAS(periodic acid schiff), alcain blue(AB) pH 2.5, AB pH 1.0, aldehyde fuchsin(AF) pH 1.7, AF pH 1.0, AB pH 2.5-PAS, AB pH 1.0-PAS and AF pH 1.7-alcian blue pH 2.5. As for the amount and histochemical composition of glycosaminglycans in Agramus agramus, most of mucous secreting columnar cell and mucous cells contain large and moderate amount of neutral glycosaminoglycans. A few of mucous cells having small amount of neutral glycosamino-glycans and minimal amount of sulfated glycosamino-glycans. In Inimicus japonicus, the esophageal mucous cells were composed of most of medium sized and large mucous cells with moderate amount of neutral glycosaminoglycanonly only, a few of medium sized and large mucous cells and most of small mucous cells with considerable amount of neutral glycosaminoglycans and minimal to small amount of nonsulfated glycosaminoglycans, and a feq of small mucous cells with small amount of neutral glycosaminoglycans and minimal amount of sulfated glycosaminoglycans. In Epinephelus chlorostigma, most of medium sized and large mucous cells were mixed small amount of neutral glycosaminoglycans with sulfated glycosaminoglycans, a few of which were contained with moderate or considerable amount of neutral glycosaminoglycans with sulfated glycosaminoglycans, while most of small mucous cells containing considerable amount of neutral glycosaminoglycans and small to moderate or considerable to minimal amount of nonsulfated glycosaminoglycans(sialomucin) a few of which containing a mixture of considerable amount of neutral glycosaminoglycans and considerable amount of nonsulfated glycosaminoglycans(sialomucin)only. In Helicolenus dactylopterus, most of medium sized and large mucous cells, mixing with moderate to considerable amount of neutral glycosaminoglycans and small to moderate amount of sulfated glycosaminoglycans, while most of small mucous cells with considerable amount of nonsulfated glycosaminoglycans (sialomucin), a few of which having a mixture of considerable amount of neutral glycosaminoglycans and considerable or small amount of nonsulfated glycosaminoglycans(sialomucin).