Composition and biomass of an Antarctic megafauna community were studied during a discontinuous 12 months cycle (March–December 1999 and December 2000–March 2001) at two stations (12 and 25 m depth) in Admiralty Bay, King George Island, Antarctica. During this period iceberg impacts were monitored in order to analyse their role in structuring the community. Organic matter content of the sediment showed a seasonal cycle for both depths, with lower values during winter and higher in summer. Composition and biomass of the megafauna were comparable to those described in previous surveys for the maritime Antarctica. Interannual or summer/winter changes in the density or biomass of the megafauna community were not significant, although significant differences between depths occurred during the whole survey. The observed community composition can be the considered result of a continuous invasion from a deeper fauna, constrained at shallower waters by the effects of ice and storms.