There is a lack of evidence on the health impact of projects that employ HCD. The A360 evaluation comprises an outcome evaluation, a process evaluation and a cost effectiveness study. The primary objective of the outcome evaluation is to assess the impact of the A360 programme on the voluntary use of modern contraception (the modern contraceptive prevalence rate, mCPR) among sexually active girls aged 15–19 years. A baseline survey is being conducted prior to the scale-up of the programme’s interventions, with an endline survey planned for 2019/2020. This report details the findings from the baseline survey in one of the three A360 countries – Nigeria.