The sedimentary succession of piston core RC26-16, dated by 14 C accelerator mass spectrometry, provides a nearly continuous palaeoceanographic record of the northeastern South China Sea for the last 15 000 yr. Planktic foraminiferal assemblages indicate that winter sea-surface temperatures (SSTs) rose from 18Β°C to about 24Β°C from the last glacial to the Holocene. A short-lived cooling of 1Β°C in winter temperature centred at about 11 000 14 C yr ago may reflect the Younger Dryas cooling event in this area. Summer SSTs have remained between 27Β°C and 29Β°C throughout the record. The temperature difference between summer and winter was about ca. 9Β°C during the last glacial, much higher than the Holocene value of ca. 5Β°C. During the late Holocene a short-lived cooling event occurred at about 4000 14 C yr ago. Oxygen and carbon isotopic gradients between surface (0-50 m) and subsurface (50-100 m) waters were smaller during the last glacial than those in the Holocene. The fluctuation in the isotopic gradients are caused most likely by changes in upwelling intensity. Smaller gradients indicate stronger upwelling during the glacial winter monsoon. The fauna-derived estimates of nutrient content of the surface waters indicate that the upwelling induced higher fertility and biological productivity during the glacial. The winter monsoon became weaker during the Holocene. The carbonate compensation depth and foraminiferal lysocline were shallower during the Holocene, except for a short-lived deepening at about 5000 14 C yr ago. A preservation peak of planktic foraminifera and calcium carbonate occurred between 13400 and 12 000 14 C yr ago, synchronous to the global preservation event of Termination I.