We explore the usefulness of physical and economic measures of emissions intensity in providing guidance for greeenhouse gas (GHG) mitigation policies for agriculture and land use. Using data from nine selected countries, the ability of various measures to illuminate options for the reduction of direct and indirect emissions from agriculture is examined. At the level of individual commodities, we show that the decomposition of physical emissions ratios can provide useful insights into options for reducing direct agricultural emissions. We argue that economic measures of emissions intensity are superior to physical measures as a guide to policy. Using data for the United States we demonstrate that mitigation priority rankings can be affected by the emissions measure used. We conclude that a measure based on value added is superior to a physical emissions measure and to a measure based on the total value of output. Use of the value-added approach has a number of analytical advantages, including the ability to reflect more comprehensively the policy set available to policymakers in pursuing mitigation and other policy objectives.