Central Chile (32–35° S) lies at the northern border of the strong influence of the westerly circulation belt and thus exhibits a steep rainfall gradient. A new core from Laguna de Tagua Tagua (34° 30′ S) provides a sedimentologic, geochemical and palynological record of regional hydrologic balance for the last 46 000 cal. yr BP. According to our age model, relatively humid conditions occurred during glacial times before 43 500 cal. yr BP and from 40 000 to 21 500 cal. yr BP. Reduced moisture conditions and likely lower temperatures occurred from 42 400–40 100 cal. yr BP. Higher lake levels, and pollen assemblages with Valdivian rainforest taxa, imply much higher precipitation during glacial times (40 100–21 000 cal. yr BP) compared to today and, therefore, enhanced westerly activity in northern Central Chile. Afterwards, the general decrease in moisture was punctuated by two abrupt arid periods at 21 000–19 500 cal. yr BP and 17 000–15 000 cal. yr BP, and two more humid intervals: 19 500–17 000 (almost coincident with the global Last Glacial Maximum, LGM) and 13 500–11 500 cal. yr BP. The early and mid-Holocene were the most arid periods in Central Chile for the studied time interval. Millennial-scale palaeohydrological reconstructions from Tagua Tagua are consistent with regional climatic records. Copyright © 2005 John Wiley & Sons, Ltd.