Modern investigation of ocean water pCO2 started during the International Geophysical Year (IGY), 1957 - 1960, with the introduction of infrared CO2 gas analyzer and gas-water equilibrator aboard oceanographic research vessels (Takahashi 1961, Keeling et al. 1965, Broecker and Takahashi 1966). Combined with high-accuracy CO2-air-gas mixtures made available for the calibrations of the analyzers at sea, the quality of seawater pCO2 data was greatly improved from that obtained in the pre-World War II era. During major oceanographic programs that took place after IGY, the CO2 analyzers and equilibrators have been steadily improved to give more frequent observations and better accuracy, although the principles of the measurement remained essentially unchanged. Computers used for system control and data logging contributed significantly to the data quality. The objective of this database is to assemble high-quality pCO2 data obtained using the equilibrator-analyzer method, and to reprocess the data using a standardized method of computation, that will be described below. Therefore, the pCO2 values listed in this database may differ from the original listings prepared by respective investigators.