During the 1999/2000 austral summer the tenth annual beach debris survey was carried out at Signy Island, South Orkney Islands. Debris was cleared each month between November andMarch from three study beaches. The debris was counted, measured and classified by type,material, mass and size categories. A total of 55 items weighing 10.78kg was collected. The number of items was 35% less than 1998/99, and the second lowest ever recorded. The total mass of the waste recovered has decreased since 1998/99 by 17% but was still the second highest since 1995/96. Plastic waste was predominant, as in previous seasons, although the proportion of plastic items (38%) was the lowest ever recorded and follows a declining trend since 1996/97. The proportion of polypropylene packaging bands removed was also the lowest recorded (18%) and may indicate that the ban on their use aboard fishing vessels brought into force by CCAMLR in 1995/96 has been effective and should continue. Classifying the waste by source revealed that 60% had come from ships or fishing vessels and7% were from Signy Research Station. The rest comprised wood (11%) and items with noobvious source (22%). Of particular concern was the quantity of polystyrene foam whichaccounted for 31% of all items recovered and 46% of items small enough to be ingested byseals and seabirds. The proportion of polystyrene foam items washed ashore has been increasing since 1996/97. It is recommended that CCAMLR should advise its members touse alternative, less persistent forms of packing material where possible. With the exception of 1998/99, the quantity of waste recorded at Signy Island has been showing a declining trend since 1993/94. This is promising. The longevity of plastics and other materials with a high resistence to degradation in the marine environment remains a problem and highlights theneed for continued monitoring to ensure that vessels are aware of, and comply with, regulations prohibiting the disposal of debris at sea.