The abundance and proteolytic activity of bacteria inhabiting the surface microlayers and subsurface water in the region of the Gda?sk Deep have been determined. Proteolytic bacteria occurred in large numbers, making up 60-100% of the total number of strains in the water layers investigated. Bacteria inhabiting the subsurface water layer displayed the highest mean activity of enzymes catalysing protein decomposition processes. The considerable impact of temperature, pH and salinity on protease activity was noted.