‘Carbon footprint’ has become increasingly used as an indicator of environmental performance for many different types of organisations, including universities. While the indicator has been widely applied, a lack of clarity on assumptions, methodological approaches and boundary issues has prevented widespread comparisons of analyses. This paper presents work that University College Cork, Ireland, (UCC) has undertaken on the measurement of its carbon footprint. UCC aims to be a leader in sustainability of the education sector. In 2010 it became the first university to be awarded the international green flag award; achieving another first for Universities in 2011 gaining ISO50001 certification; while at the start of 2013 it was placed #3 in the UI GreenMetric World University Rankings. In the context of these efforts, the University’s Carbon Footprint is an important metric for the organisation, with UCC's experience holding potential relevance for other institutions in the higher education sector. The initial study, in accordance with the WRI/WBCSD Greenhouse Gas Protocol Corporate Accounting and Reporting Standard, including scope 1, 2 & 3 emissions, was performed for the 2008- 9 academic-year with a follow-up study for 2011-12. The experience of carrying out a carbon footprint study in a university is presented. The methodological and practical issues involved are reported in detail, including an exploration of issues associated with temporal comparisons. Approaches of other studies are considered and the paper forwards best- practice recommendations for the use and communication of such metrics across the higher education sector, and more broadly.