Food loss and waste (FLW) is an important issue in Canada, Mexico, and the United States, where almost 170 million tonnes of the food produced for human consumption is estimated to be wasted across the supply chain (CEC 2017b), while food security and resource efficiency are considered top priorities of the national social, environmental and development policies. The Operational Plan of the Commission for Environmental Cooperation 2015–2016 (Operational Plan 2015–2016) established the North American Initiative on Food Waste Reduction and Recovery as part of its green economy and climate change portfolios. This work is a continuation of previous work and is delivered under the measurement and mitigation of food loss and waste project in the Operational Plan of the Commission for Environmental Cooperation 2017–2018 (Operational Plan 2017–2018). This technical report is one of two outputs for quantifying FLW and surplus; the other is a practical guide. The report discusses the methods for quantifying FLW and surplus across the supply chain and the approaches for estimating environmental, financial and social impacts caused by FLW and food surplus. It includes detailed information that supports the practical guide, allowing the latter to be a more user-friendly document. The two documents are designed to help governments, the food industry, business, institutions and nonprofit organizations better understand FLW and surplus measurement at each stage of the food supply chain within North America.