Results of the monitoring of the Gulf of Gdańsk environment are included in this archival data set. The measurements were conducted by the Institute of the Oceanography of the University of Gdańsk (IO UG) from 1981 till 1994 at the fixed sampling stations covering the area located between Hel Peninsula and the coast of the Gulf of Gdańsk, which extended to the Vistula Spit (Krynica Morska) in the east. Field campaigns took place several times during each year. Water physical and chemical properties were determined at the standard depths in the water column. The list of measured parameters includes water salinity and temperature, light-beam attenuation at 535 nm, concentration of biogenic substances, oxygen content as well as water pH. Water transparency was estimated with the use of Secchi disc. The weather conditions during measurements are represented by wind speed and direction (azimuthal angle), cloud cover (0-10 scale), psychrometer readings (dry and wet bulb temperatures). Ice and sea state observations are also given. Manuscripts of annual reports from the monitoring edited by dr Jacek Nowacki, e.g. Nowacki J. et. al., 1986, “Research on hydrology and hydrochemistry of the Gulf of Gdańsk in 1986” (in Polish|), IO UG, are available at the Oceanographical Reading Room, 81-378 Gdynia Poland, Al. Marszałka Piłsudskiego 46.