We conducted three weeks of seismic observations at the Rodriguez Triple Junction (RTJ) in the Indian Ocean using 18 ocean-bottom seismometers over an area of 90 km¿90 km. We identified six teleseismic events and obtained significant anomalies in the relative travel-time residuals of the teleseismic P-waves. The residuals are positive at the RTJ, the northern part of the Southeast Indian Ridge (SEIR), and the eastern side of the Central Indian Ridge (CIR), and are negative at and around the Southwest Indian Ridge (SWIR). It is suggested that there is a relatively hotter mantle under the triple junction and the northern part of the SEIR segment, along-axis variations in mantle temperature along the SEIR segment, and cooler mantle under the SWIR segment. The CIR segment has an asymmetrical distribution of relative residuals. ¿ American Geophysical Union 1996