Much of the existing literature on the demographic impact of family planning programs focuses on their role in increasing contraceptive use, which, in turn, accelerates fertility decline. What is not clear, however, is whether this effect operates solely through a reduction in unmet need brought about by eliminating obstacles to use or whether and to what extent the programs also affect demand for contraception through messages concerning the benefits of family planning. This article aims to shed additional light on this issue by analyzing data drawn from recent Demographic and Health Surveys conducted in 63 developing countries. The first section reviews general levels and trends in unmet need, demand, and use over the course of the fertility transition. The second section presents different types of evidence of program effects, including results from a controlled experiment and from country case studies. The evidence indicates a program impact on both unmet need and demand.