The Working Paper summarises the main findings and recommendations of the pilot study, including first orders of magnitude of TOSSD flows to Nigeria. Estimated TOSSD flows to Nigeria in 2016 amounted to approximately USD 3 billion of official development finance and USD 1.9 billion of private finance mobilised through official development interventions. These first orders of magnitude have been estimated using OECD DAC Statistics. However, these figures are likely to be largely underestimated due to information gaps, notably on the People’s Republic of China (hereafter China) and emerging providers’ official support to Nigeria. The results of the pilot also indicate that the current organisational set up of Nigeria, both from an institutional and an IT system perspective, makes it challenging for the Government to access, collate, collect analyse and use data on external financing to the country using national data.The TOSSD pilot in Nigeria confirmed the usefulness of country pilots for testing the TOSSD methodology and for ensuring feedback by partner countries on TOSSD as a measurement framework. The findings also helped to ascertain that the International TOSSD Task Force developing the framework is in the right direction with regard to the main parameters of the measure. Findings contained in the present Working Paper will support the discussions to refine the emerging TOSSD Reporting Instructions in 2018 and 2019.