Actively studying take-up rates, or participation rates, can help us understand the demand for different microfinance products, and how existing products might be improved to attract more clients and serve them better. This note reviews the evidence on take-up. It first discusses why take-up rates and participation are important, and how they can be measured. It then goes on to review survey data on why people don’t use microfinance products when they are available, and offers guidance on how low take-up rates might be addressed.