Aliphatic (AHs) and polycyclic aromatic hydrocarbons (PAHs) concentrations were measured in marine surface sediments around the Brazilian station in Admiralty Bay, during the summers of 1997/98 and 1999/2000 using GC-FID and GC-MS. Total aliphatic hydrocarbons ranged from 0.15 to 13.28 μg·g−1 (dry weight) while n-alkanes varied between 0.10 and 9.63 μg·g−1. The highest concentrations were obtained at the sewage outfall, with decreasing levels away from the outfall. The distribution of n-alkanes showed significant quantities of long chain n-alkanes (n-C22 to n-C34) at sites near the Brazilian station that may be attributed to the station activities. A short chain n-alkanes sequence (n-C12 to n-C21) associated with diesel fuel arctic (DFA) was present in all the samples. Total PAHs varied from 9.45 to 270.5 ng·g−1. The higher PAHs level and the presence of an unresolved complex mixture only in sediment from the sewage outfall is an indication of oil contamination at this location. A slight increase in PAHs near the Brazilian station since 1993 may be attributed to an increase in the number of staff over recent years. In general, the concentration of AHs and PAHs was similar to that found in other Antarctic areas.