Abstract Food systems encompass interconnected actors and activities that bring food from farm to fork and the broader environments (economic, societal and natural) they are embedded in. Food systems operate at high cost to human and environmental health. 20-30% of total human-created greenhouse gas (GHG) emissions globally are attributable to food system activities. The agri-food sector plays a vital role in the Irish economy. In 2021 agri-food exports valued €18.7 billion and provided 7.1% of jobs in Ireland. Economic growth in the sector has come at the expense of the environment. In 2018 Ireland had the highest GHG emissions from food systems per capita in the EU. This paper presents an overview of GHG emissions from Irish food system activities 1990-2018. Data from the Emissions Database for Global Atmospheric Research were used to examine changes in food system emissions (Mt C02-equivalent(eq)) over time (1990-2018). Shares of total emissions by system stage (land use, production, processing, packaging, retail, transport, consumption and food waste) were also analysed. Food and agriculture policy developments were mapped to changes in emissions over time. After a decline from 2000 to 2011, food system emissions in Ireland are trending upwards. Total food system emissions in Ireland in 2018 measured 34Mt (C02-eq), accounting for 52% of all Irish emissions. 84% of food system emissions arose from production. Packaging and transport of food represented 3.7% each and consumption amounted to 0.84%. Increasing sustainability in the food system requires an understanding of where and how emissions arise across the whole system. Research on Irish food-related emissions has focused on agriculture and land use but little is published on activities later in the system. Estimating GHG contribution across the Irish food system this analysis provides important information for targeted policy development for mitigating food system impacts on climate change and health. Key messages • By estimating GHG contribution across the Irish food system this analysis provides important information for targeted policy development for mitigating food system impacts on climate change. • Increasing sustainability in the food system requires an understanding of where and how emissions arise across the whole system.