During late March and April 1961, the USCGC EASTWIND (WAGB-279) occupied 30 oceanographic stations in the Indian Ocean. Three sections were made, one running from off Cape Leeuwin, Australia west as far as 78 E. longitude, a second continuing north from this point to 40 N. latitude, and the third which continued west to just south of Socotra Island. Measurements were made of temperature, salinity, and dissolved oxygen; and from these data density, sound velocity, and percentage of saturation of dissolved oxygen were derived. Transparency was determined by Secchi disc, and the Deep Scattering Layer was observed. Continuous recording of bottom depths by echo sounder was carried out through a region where few soundings had hitherto been reported. Northward reaching tongues of Antarctic Intermediate water are shown on the southern profile and on the southnorth profile along the 78 E. meridian. In mid-Indian Ocean, these masses push up toward the surface causing a divergence which is apparent in the salinity and dissolved oxygen profiles. Also delineated are high salinity waters with very low oxygen content which come from the Arabian and Red Seas. The Deep Scattering Layer disappears in mid-Indian Ocean and reappears again to the north, following a similar pattern to that already observed in the Pacific Ocean. (Author).