This paper presents a framework of the costs or constraints in the use of fertility regulation, reviews the existing knowledge on the subject in a cross-cultural context, and indicates the need for further studies. It is suggested that the apparent contradiction noted in fertility surveys between a couple's desire to have no more children or to postpone the next birth and actual behavior can be explained by the costs involved in the use of fertility regulation methods. The costs of fertility regulation can be broadly classified into 4 categories: 1) physical/health (disruption of menstrual cycle, side effects and health hazards of contraceptive methods, perceived health hazards based on ethno-physical concepts, and sacrifice of sexual pleasure); 2) psychic (violation of sexual modesty and human dignity, conflict with religious beliefs; 3) social opinion (challenges to spouse and sex role expectations, challenges to social influence group); and 4) economic (money, time). The economic costs of fertility regulation to individuals vary greatly according to the presence or absence of public sector family planning programs. A substantial part of these costs could be eliminated by national and international programs. So far, no study has focused on the costs of fertility regulation and factors affecting them. A methodology that combines elements of both a questionnaire survey and anthropological investigation and collects data on both the individual and community levels may be most amenable to assessing the impact of costs on the use or nonuse of fertility regulation.