An estimated 218 million women across low- and middle-income countries (LMICs) have an unmet need for contraception: that is, they want to avoid a pregnancy but are not using modern contraceptives. Mass media reaches a large share of the population in these countries, but how effective is it in changing behaviors? To answer this question, Development Media International (DMI) conducted a randomized controlled trial to evaluate the impact of an intensive, 30-month radio campaign in Burkina Faso that promoted family planning. The trial was funded by the Global Innovation Fund (GIF), Development Innovation Ventures (DIV) of the United States Agency for International Development (USAID), and an individual philanthropist.