The objective of these investigations was to determine the viability of selected Gram-negative and Gram-positive bacteria exposed to high pressure and subzero temperature, in the range of 60÷193 MPa and –5 ÷ –20°C, without freezing of water. The results showed that similarly to the process conducted at the temperature above 0°C, Gram-negative bacteria and cells in the exponential growth phase are more sensitive to pressure treatment than the Gram-positive bacteria and cells being in the stationary phase of growth. Variations in resistance of microorganisms to high pressure were observed not only among the different species of bacteria but also among the strains belonging to the same species. Both pressure-sensitive and pressure-resistant strains appeared within mesophilic, psychrotrophic and thermophilic bacteria. However, the tendency to greater pressure sensitivity of Gram-negative psychrotrophic and psychrophilic strains than of the Gram-negative mesophiles was emphasized. The temperature of growth influenced the microorganisms’ sensitivity to pressure.