This article investigates the influence ofparticipation in andexposure to voluntary associations on fertility-limitingbehavior. Its theoretical framework, drawnfrom the sociological literature on social networks and voluntary associations, the demographic literature on program participation, and the literature on health behavior, delineates the mechanisms through which participation in voluntary associations is likely to influence permanent contraceptive use. The article draws from three data sources to empirically testtheframework: individual-level surveydata from couples residing in the ChitwanValley in south-central Nepal; data on the neighborhoods ofthe Chitwan Valley collected usingan integrated application of ethnographic, survey, and archival methods; and the authors' own ethnographic interviews in these neighborhoods. Empirical analyses showthatparticipation in a range of voluntary associations increases permanentcontraceptive use. Furthermore, livingin a neighborhood with a voluntary association increases permanent contraceptive use. Finally, participation in different types of voluntary associations -including creditgroups, women's groups, agricultural groups, and youthgroups -appears to besimilarly related topermanentcontraceptive use. " The third and fourth authors contributed equally to this article; their names are listed alphabetically. We would like to thank N.E. Barr, Shara Neidell, William Axinn, and the anonymous Social Forces reviewersfor helpful suggestionsand comments on an earlier draft of