The Convention on the Conservation of Antarctic Marine Living Resources states as part of its objective the maintenance of ecological relationships and the prevention of irreversible changes to the ecosystem. The Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) has implemented an Ecosystem Monitoring Programme (CEMP) for the Antarctic marine environment to give effect to this requirement. The design phase of the programme took three years. The programme has been fully implemented since 1987 and involves monitoring selected predator, prey and environmental indicators of ecosystem performance. The central aim of the programme is the detection of changes in these indicators and the interpretation as to whether these changes are due to natural events or the harvesting of marine living resources. The core of the programme is the acquisition, centralised storage and analysis of standardised monitoring data combined with a strong emphasis on empirical and modelling based research. This both modifies the monitoring approach in line with changing requirements and creates a sound scientific background against which to test the effects of management options on components of the Antarctic ecosystem. The development of procedures for translating monitoring results into management advice is a critical part of the programme. Management takes the form of the regulation of fishing activities. Since 1987 CEMP has collected data on six bird and seal species at 15 sites around the Antarctic. Up to 14 parameters of predator performance and 10 parameters of prey and environmental performance are collected at each site. The data sets collected by CEMP form an extremely powerful tool for understanding and managing the Antarctic marine ecosystem.