OBJECTIVES: Healthcare systems have a significant environmental impact and, thus, indirectly affect public health. In order to improve current practices, a better understanding of the actual environmental impact generated by surgical procedures is necessary. METHODS: An eco-audit methodology was carried out to assess the greenhouse gas emissions arising from conventional isolated cardiac surgery procedures. This inquiry took into account 3 workstations (the surgical, the anaesthesia and the cardiopulmonary bypass workstations). All wastes were analysed including the disposable medical products, pharmaceuticals and energy consumption during such surgeries. RESULTS: Twenty-eight cardiac surgeries were analysed out of a 4-week study period. The mean emissions during a single cardiac surgery was 124.3 kg of carbon dioxide equivalent (CO2-e). Eighty-nine per cent of the total emissions was related to the use of disposable medical products. The environmental impact of pharmaceuticals used at anaesthesia workstations was 12.4 kg of CO2-e (10% of total greenhouse gas emission), with 11.1 kg of CO2-e resulting from the use of halogenated gas. Direct electrical consumption resulted in 4.0 kg of CO2-e per surgery (3% of all emission), including lighting and air conditioning. CONCLUSIONS: Conventional isolated cardiac procedures yield the global warming equivalent of a 1080 km plane ride for a single passenger. The environmental impact of such life-saving interventions, therefore, must be put in perspective alongside pollution induced by 'non-indispensable' human activities. However, numerous initiatives at the local and individual level as well as at a larger systemic and countrywide scale appear to provide accessible pathways to meaningfully reduce greenhouse gas emissions during cardiac surgery.