The purpose of this document is to describe the elements in National Forest Monitoring Systems (NFMSs) as they relate to REDD+ under the United Nations Framework Convention on Climate Change (UNFCCC), and to describe the UN-REDD program approach to Monitoring and Measurement, Reporting and Verification (M & MRV) requirements. This paper is presented in a series of sections discussing the various elements of relevant texts of the UNFCCC and the methodological recommendations of the Intergovernmental Panel on Climate Change (IPCC). This approach aims to allow the end-user to consider the implications of, and steps involved in, the implementation of REDD+ activities in distinct national contexts.