If offered an opportunity to save via formal financial services, will youth in developing countries participate, save, and accumulate assets? This is one of the key questions in YouthSave, a savings initiative implemented in four developing countries, targeting youth aged 12 to 18 years, from predominantly low-income households. This report presents two-year findings from a study that tracks account uptake and saving patterns and performance in youth savings accounts in four countries: Colombia, Ghana, Kenya, and Nepal. This savings demand assessment (SDA) is ambitious in its attempt to include systematic data on as many youth savers as possible. The result is a very large dataset that enables us to report in detail who is saving, and factors associated with saving patterns and performance. The report is divided into four sections: the ten key findings; the project summary; the body, which consists of Chapters 1 through 9 and summarizes information across all four countries; and the appendices, which include country-specific details and summary tables. A summary of findings appears at the end of each chapter.