Deep-ocean temperature, salinity and dissolved oxygen observations in the eastern South Pacific Ocean col-lected during the late austral fall in 1995 are compared with observations made there 28 years earlier during the same season and similar El Niño-Southern Oscillation phase. Warming observed above 800 m at 43 • S reflects the produc-tion of warmer Subantarctic Mode Water in recent decades. Warming observed above 1600 m at 28 • S is due to downward isotherm displacement and southward movement of water masses by 100-200 km, as revealed by joint analysis of tem-perature and oxygen data. Such changes would be expected for a weaker subtropical gyre in the South Pacific. An ob-served oxygen decrease between about 1800 m and 2900 m at 28 • S may indicate enhanced southward, boundary current flow at mid-depths off Chile.