Concentration-depth profiles of excess 230Th have been measured in five sediment cores from the central Indian Ocean Basin to determine their accumulation rates and excess 230Th flux to the depositional environment. Sedimentation accumulation rates ranged between 1 and 5 mm ky −1. The excess 230Th inventories in the cores range from 44 to 481 dpm cm −2, considerably lower than that expected from its production in the overlying water column. These low excess 230Th inventories (relative to its production) have been attributed to the effects of winnowing by bottom currents. The absence of 230Th ex in core (SK-176) has been attributed to the lack of sediment deposition in this area caused by the influence of Antarctic Bottom Water (AABW). This study shows that the deposition of biogenic silica and lithogenic components exhibited orders of magnitude variations durining Late Pleistocene. The biogenic flux variation are attributed to productivity changes while the episodic variations in the non-biogenic flux could result from major changes in the influx of terrigenous materials via the Ganges-Brahmaputra.