The management of sediment and water contamination from legacy waste is a significant problem in Antarctica. Although several reports have noted that there are contaminated sites at the abandoned Wilkes Station, a systematic attempt to assess the spatial scale of the problem has not been made, making development of clean-up or preservation programmes difficult. A contaminated site assessment for the old Wilkes Station and surrounds is presented in this paper. The Australian and New Zealand Environment and Conservation Council (ANZECC) sediment and water quality guidelines and background concentration levels (BCL) were used to assess the extent of contamination across Clark Peninsula. Of 67 sediment sites sampled, 72% were contaminated with at least one metal or metalloid, with values exceeding the ANZECC ISQG-High or 2 x BCL. Moreover, 19% were contaminated with four or more metals/metalloids. Of the 93 water samples collected, all but one was contaminated with at least one metal/metalloid concentration exceeding the guidelines, and 96% were contaminated with two or more metals/metalloids. For hydrocarbons in sediment and water, most samples were below quantitation limits. There is a complex pattern of contamination across Clark Peninsula that needs to be considered in future waste treatment, containment or removal operations, and for protection of heritage items.