The purpose of this Guidance Document is to identify possible and suitable approaches to the evaluation of chemicals impact, and in particular plant protection products’ impact, on soil organic matter breakdown. The test method and procedures describes in this document are mainly based on previous studies conducted in Europe to address the European regulation; other OECD member countries may not currently have similar data requirements for agricultural chemicals. However, methods identified in this document, and specifically the litter bags test method, add important tools to a battery of existing standardised protocols for assessing chemical impacts on the soil biota communities. Procedures outlined in this Guidance Document are primarily intended for the evaluation of agricultural chemicals but they can also be applied to ecological risk assessment activities at contaminated sites, as well as to laboratory chemical toxicity testing.