From February 1,1979 to January 31,1980,thirty men of the wintering party of the 20th Japanese Antarctic Research Expedition executed the observation and examination in many scientific projects, particularly laying emphasis on "Polar Experiment-South (POLEX-South)" as one of the subprograms of the Global Atmospheric Research Program (GARP) and on the geological survey as the first year of "Analysis of crustal structure of Antarctica". The former project was carried out around Mizuho Station, and at an unmanned meteorological station "Y 100" which was established at 71.3°S and 46.3°E (2600m above sea level), and much results were obtained about the heat budget in the inland highland (katabatic zone) of the Antarctic Continent. As for the latter project, long term geological survey and search for meteorites around the Yamato and Belgica Mountains were made from October to January. About 3000 pieces of meteorites were found and collected. At Syowa Station, in addition to the routine observation of aurora, geomagnetism, ionosphere, meteorology, seismology and ocean tide, reception of data signals from scientific observation satellites and observation of ionospheric disturbance in the polar region by the upper atmosphere section, monitoring of minor constituents such as CO_2 and NOx and sampling of rocks by the environmental science section, and research in medical science were performed throughout the year.