A piston core was obtained from the Korea Plateau at the water depth of 1259 m to understand late Pleistocene paleoceanographic change. Core sediments consist of four lithologic facies: bioturbated mud (BM), crudely laminated mud (CLM), massive muddy sand (MS), and tephra layers (TL). Alternation of BM and CLM facies are widely distributed throughout the core, this may imply the variation of glacial and interglacial paleoceanographic conditions. The chronostratigraphy of the core was established using five radiocarbon ages, the oxygen isotope curve of the planktonic foraminifera, total organic carbon contents as well as lightness variation of the sediments. The core bottom represents marine isotope stage (MIS) 8, and spans more than 300 kyr of paleoceanographic history of the East/Japan Sea. Considerable amounts of authigenic gypsum were found throughout the core. Mineralogic identification of the gypsum was confirmed by X-ray diffractometry (XRD) and energy dispersive spectrometer (EDS). Authigenic gypsums in this core can be classified into four types: hexagonal tabular, hexagonal columnar, spheric, and prismatic forms. The size of authigenic gypsums are quite varied and average about 1000 ㎛, 700 ㎛, 2000 ㎛, and 300 ㎛ in greatest dimension for each types. Scanning electron microscopic (SEM) examination revealed numerous sharp leaching grooves on the surface of the gypsum in several layers. The authigenic gypsums do not seem to be associated with planktonic foraminifera and total organic carbon contents but broadly tend to be concentrated in the bioturbated mud layers. If the origin of the SO42- and Ca2+ ions and the formation process of the gypsums can be determined, it will help to understand the paleoceanographic variations of the East/Japan Sea.