Measurements of total gaseous mercury (TGM) were carried out in the Polish coastal zone of the Gulf of Gdansk from Hel, situated at the end the tip of the Hel Peninsula, to Piaski in the Vistula Pit. The results were recorded in the atmosphere 150 cm above the ground using an automatic analyzer Gardis 1A in March, April and May 1999. The mercury concentration over the coastal zone of the Gulf of Gdansk did not exceed maximum permissible levels and were at levels similar to those in other maritime regions of the Baltic Sea and the North Sea. The average concentration of mercury was 3.4 ng m-3. Increased TGM concentrations of approximately 8.2 ng m-3 occurred locally near the sewage treatment facility in Sztutowo, on the tip of the Hel Peninsula and in the Tri-Cities near the industrial areas of shipyards and the harbor. No increased concentrations of gaseous mercury were registered in the vicinity of the heat and power plant or the refinery as chimneys release fumes at high altitudes. What is more, the mercury concentrations recorded in the forests of the Vistula Lagoon and the Hel Pit were nine times lower than the average concentration. Laboratory experiments carried out on samples of sea water from three coastal measurement stations proved that mixing in the sea surf zone influences the emission of mercury from the water into the atmosphere. The emission of gaseous mercury from the surface waters of the Gulf of Gdansk was higher in March when the life processes in the water were still slow and bio-accumulation was very limited.