Oxygen isotopic and microfaunal analyses and shell size variations of Orbulina universa in two Indian Ocean cores indicate that the position of the Subtropical Convergence has fluctuated between a northern limit north of 31 degrees S during glacial stages and its present, maximum southern limit. The northward displacement of the Subtropical Convergence to a position off Durban, South Africa, reflects the general weakness of the Agulhas Current during glacial stages and parts of interglacial stages, representing about 65 percent of the past 540,000 years.