The whole brain atlas of the eel was constructed in the first place by Klüver-Barréra's staining. Eighty onenuclei and thirty fiber tracts were identified in the present study. Basically, the brain topology of the eel wassimilar to that of the rainbow trout, the goldfish, the zebrafish, and the catfish. However, some details differedfrom those of other teleosts. The parvocellular preoptic nucleus (PP) was not subdivided, whereas the anteriorPP is distinguished from the posterior part in the zebrafish and the rainbow trout. The intermediate thalamicnucleus was not distinguished, whereas it is identified in the zebrafish, the goldfish, and the rainbow trout. Theparaventricular organ (PVO) was single, while paired PVOs are observed in the zebrafish. The torus semicircularis(TS) was smaller than that in the goldfish and rainbow trout. The cell size of the nucleus of medial longitudinalfascicle (NMLF) in the tegmentum was larger than that in the glass knifefish and the zebrafish. The protrusionof the nucleus lateralis valvulae (NLV) into the mesencephalic ventricle (VMes) was larger than that in thezebrafish and the rainbow trout. The valvula cerebelli was smaller than those in the goldfish and the zebrafish.The facial lobes (LVII) ran through the medulla oblongata (MO), whereas the two lobes fuse at the caudalcerebellum in the goldfish, the catfish, and the zebrafish. The expansion of the vagal lobe (LX) in the caudalMO was smaller than that in the goldfish and the zebrafish. The glossopharyngeal motor nucleus (MNIX) andthe vagal motor nucleus (MNX) were fused to make a columnar structure named glossopharyngeal-vagal motorcomplex (GVC). Such a columnar complex seems to be common in fishes, since similar columns are observedin the lamprey, the elasmobranch and other teleost fishes. The facial motor nucleus (MNVII) was separatedfrom the GVC, whereas it is fused with the GVC in the sturgeon, the reedfish and the tarpon.