This document explains how the organic sector can contribute to and make use of Full Cost Accounting3 (FCA), using it as a lens and methodology for shaping agriculture and food systems toward sustainability. The document outlines how we can use FCA to monitor and improve the performance of organic systems, substantiate our messages on the benefits of organic agriculture to consumers and advocate for policies that promote truly sustainable agriculture and food systems. The context here is production and consumption stemming from agriculture, although we acknowledge that agriculture touches other systems, and that implementing changes in agriculture-based systems through full cost accounting entails changes outside the boundaries of systems in agriculture.