Social Capital is created through the patterns of interdependence andsocial interaction that occur within a population, and we attempt to understand the participatory consequences of these patterns relative to the effects of human capital and organizational involvement. The production of social capital in personal networks was examined with the use of social network and participation data from the 1992 American study of the Cross National Election Project. The results suggest that politically relevant social capital (that is, social capital that facilitates political engagement) is generated in personal networks, that it is a by-product of the social interactions with a citizen's discussants, and that increasing levels of politically relevant social capital enhance the likelihood that a citizen will be engaged in politics. Further, the production of politically relevant social capital is a function of the political expertise within an individual's network of relations, the frequency of political interaction within the network, and the size or extensiveness of the network. These results are sustained even while taking account of a person's individual characteristics and organizational involvement. Hence, the consequences of social relations within networks are not readily explained away on the basis of either human capital effects or the effects of organizational engagement.