In this paper we examine the experience of one poor country, Guatemala, that provided childhood immunization partly through a major national campaign, and provided pregnancy-related services through government health facilities, during the 1980s. Specifically, we compare the breadth of coverage of these two types of services using national sample survey data collected in 1987. We then draw upon results of previous qualitative studies to explore the social, cultural, and organizational factors that may account for differences between the use of immunization and the use of pregnancy-related health services.