We examined prokaryotic biomass (PB) and prokaryotic heterotrophic production (PHP) during spring and summer in three Antarctic areas: Bellingshausen Sea, Bransfield Strait and Gerlache Strait in December 1995 and in January–February 1996. The data gathered allowed comparisons among areas, between seasons, and with the RACER study, carried out 10 years earlier in the same zone (Deep-Sea Res. 38 (1991) 1029). Prokaryotic numbers ranged from 0.67 to 13.3×105 cells ml−1, with a mean of 3.86×105 cells ml−1.