Seventeen species of gonostomatid fishes, exclusive of the genus Cyclothone, were taken on cruises 3 (10°Nto 45°S along 60°E) and 6 (18°N to 40°S along 65°E) of the R/V ANTON BRUUN during the International Indian Ocean Expedition. Bonapartia pedaliota, Danaphos oculatus, Gonostoma atlanticum, and Woodsia sp., were found mainly in the Indian Equatorial Water Mass, and did not enter the oxygen-poor water of the Arabian Sea. Gonostoma bathyphilum, Photichthys argenteus, Vinciguerria attenuata, and Vinciguerria poweriae had their centers of abundance in the Indian Central Water Mass. Gonostoma elongatum, Ichthyococcus ovatus, Valenciennellus tripunclulatus, and Vinciguerria nimbaria were encountered throughout both water masses. Of these four species, only Valenciennellus does not enter the Arabian Sea. Margrethia obtusirosira, Ichthyococcus elongatus, I. irregularis, Diploplios taenia, and Diplophos sp., were taken but rarely; all seem rather restricted in their ranges. There is good correspondence, although by no means complete, between the kinds of patterns species exhibit in the Indian Ocean and the kinds they exhibit in the much-better-known North Atlantic.