This document proposes a methodology to map policy instruments to their greenhouse gas (GHG) emission base. It seeks to support the efforts under the Inclusive Forum on Carbon Mitigation Approaches (IFCMA) to enhance the understanding of countries’ climate change mitigation policies by providing a comprehensive and systematic stocktake of policy instruments and establishing a corresponding database. The GHG mapping methodology is designed to be inclusive, covering a broad set of policy instruments relevant for climate change mitigation and is being applied to country pilot studies under the IFCMA. It develops several key concepts and definitions and proposes a five-step approach that focuses on a policy instrument’s administrative design, policy regulatory base and the legal obligations established under the regulatory framework. Finally, it presents two GHG mapping examples drawn from one of the first IFCMA pilot studies (Chile).