Since the 1960s, survey data have indicated that substantial proportions of women who have wanted to stop or delay childbearing have not practiced contraception. This discrepancy is referred to as the “unmet need” for contraception. The traditional interpretation, that these women lack access to contraceptive supplies and services, has led in turn to an emphasis on expanding family planning programs. This study analyzes survey data and related anthropological studies on the causes of unmet need and concludes that the conventional explanation is inadequate. Although for many environments geographic access to services remains a problem, the principal reasons for nonuse are lack of knowledge, fear of side effects, and social and familial disapproval. This finding underscores the need for expanded investment in services that not only provide contraceptives, but also attend to closely related health and social needs of prospective clients. Programs are likely to be most successful when they reach beyond the conventional boundaries of service provision to influence and alter the cultural and familial factors that limit voluntary contraceptive use.