The enhanced transparency framework (ETF) under Article 13 of the Paris Agreement (PA) builds on and enhances the existing transparency arrangements under the UN Convention on Climate Change (UNFCCC). The objective of this paper is to identify to what extent the existing reporting of greenhouse gas (GHG) inventories and mitigation actions by developing countries are already in line with new reporting requirements under the ETF at the time of submitting their latest biennial update reports (BURs) in October 2019. The paper found that the majority of the 50 developing countries analysed are in line with the ETF requirements for “use of IPCC inventory guidelines”, “reporting of GHGs” and “reporting of gases affected by mitigation actions”. On the other hand, only a minority of them have met the ETF requirements for “use of Global Warming Potential (GWP)”, “reporting of consistent annual time series”, “latest reporting year” and “projections of national GHG emissions”. Detailed reporting related to Article 6 will also be new to many developing countries. These areas are the most critical for developing countries to prepare for reporting GHG inventories and mitigation actions under the ETF.