A proposal for a SCOR “Working Group to identify Ecosystem Essential Ocean Variables for measuring change in the biological properties of marine ecosystems” was developed by members of the Southern Ocean Observing System (SOOS) Science Steering Committee in conjuction with discussions amongst members of the Science Steering Committee of the IMBER program, Integrating Climate and Ecosystem Dynamics (ICED) as part of the development of the ICED Southern Ocean Sentinel. The aim of the Working Group is to develop a set of essential variables for monitoring that would contribute to assessments of whole-of-ecosystem status and change. The intention of the SCOR Working Group is to provide a mechanism for linking a number of groups working on this issue, leading to a symposium in 2016. The proposal is detailed in this paper. It is recommended that the Scientific Committee of CCAMLR become involved in this work, particularly through the Working Group on Ecosystem Monitoring and Management and the experts involved in the CCAMLR Ecosystem Monitoring Program. The outcomes of this working group will be important for CCAMLR in measuring the status and trends of Southern Ocean ecosystems, particularly in support of the development of management procedures for fisheries and in the conservation of marine biodiversity.