Since 2005, the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) has progressed plans to implement spatial management for purposes of marine conservation (i.e. networks of Marine Protected Areas, or MPAs). In 2008 CCAMLR utilized a circumpolar-scale ‘bioregionalisation’ to identify areas within which MPA designation should be considered as a matter of high priority. Members have been encouraged to progress spatial management planning at regional scales, using both fine-scale bioregionalisation and ‘systematic conservation planning’ (SC-CAMLR XXVII, paragraph 3.55). In 2009 the CCAMLR Scientific Committee agreed a series of milestones to achieve a representative network of MPAs in the CCAMLR Area by 2012. New Zealand has been an active contributor to the CCAMLR spatial management planning process, and has declared its interest in progressing spatial marine protection in the Ross Sea region. To this end, in June 2009 New Zealand hosted a Ross Sea Region Bioregionalisation and Spatial Ecosystem Processes international expert workshop, tasked with assembling and analysing available environmental and biological spatial data for the Ross Sea region and summarizing this information to inform spatial management design, consistent with CCAMLR endorsed methods. The workshop met for five days and was attended by twenty-one international experts with a range of relevant expertise. Analytical methods were as in previous CCAMLR Bioregionalisation workshops (Grant et al. 2006, SC-CAMLR XXVI/9), i.e. automated environmental classification using cluster analyses of environmental datasets, iteratively selected and validated with reference to expert knowledge and spatial biological data, with additional expert consultation to identify areas containing ecosystem processes of particular importance. Outputs from the workshop include the following: i) a fine-scale benthic bioregionalisation of the Ross Sea region; ii) a fine-scale pelagic bioregionalisation of the Ross Sea region; and iii) an agreed list and map of spatially bounded ecosystem processes of particular importance for conservation of the regional ecosystem. The purpose of this paper is to describe the 2009 Ross Sea region Bioregionalisation and Spatial Ecosystem Processes expert workshop -- including available input data, workshop methodology, and workshop outputs -- and to present these outputs for consideration by CCAMLR and the wider Antarctic science and marine management community, to inform spatial management planning in the Ross Sea region. In isolation any one of the three main workshop outputs provides an incomplete picture. It is New Zealand’s intention that these three outputs be utilized together to guide ongoing efforts by New Zealand and other CCAMLR Members to design and implement a representative and effective marine spatial protection and management network, to safeguard the environmental values and ecosystem integrity of the Ross Sea region while providing for rational use, consistent with the CCAMLR mandate.