Seismic reflection data from the southern Mozambique Ridge, Southwestern Indian Ocean, show indications for a modification in the oceanic circulation system during the Neogene. Major reorganisations in the Indian Ocean circulation system accompanying the closure of the Indonesian Gateway led to the onset of current controlled sedimentation in the vicinity of the Mozambique Ridge at ~14 Ma. The modifications in water mass properties and path are documented in changes in reflection characteristics in the Mozambique Ridge area. Correlating these with identified changes of the Nd isotope evolution in deep water masses the general present day large scale circulation in the southern Indian Ocean is suggested to have prevailed for the last 9 Ma. References should not be included in abstracts.