To the Editor — We agree with Reganold and Wachter1 that organic farming offers lessons for improving agricultural sustainability. However, current organic certification systems do little to prevent deforestation and other forms of habitat conversion. For example, the USDA organic standard, widely applied around the world, failed to prevent deforestation for organic sugar in Paraguay2. The certification criteria recommended by the International Federation of Organic Agriculture Movements (IFOAM) specify that organic farms should not be established on “land that has been obtained by clearing of High Conservation Value Areas in the preceding 5 years”3, but fail to elaborate how these areas should be identified, by whom, and how compliance is audited. Rigorous assessment of land-use change cannot be left to individual, poorly resourced auditors4. The organic movement must learn from other sustainability standards, such as the Roundtable on Responsible Soy and the Rainforest Alliance, which provide more rigorous protection for forests and other habitats. This will become increasingly pertinent as interest in finding ways to end habitat loss intensifies, and as companies commit to deforestation-free supply chains.