Analysis of variance indicated that Whites had different perceptions of social capital compared to other groups, in measures of social participation, neighborhood cohesion, trust, and norms of reciprocity. Logistic regression analysis showed that individual-level social capital, measured by trust and norms of reciprocity, was weakly associated with illicit drug use. However, individuals with higher social participation were less likely to have used illicit drugs ever or during the month prior to the interview. The association between social capital and illicit drug use is discussed, as well as the role of social participation in illicit drug use. Rather than an individual-level measure of social capital, future research should employ a neighborhood-level measure of social capital that aggregates neighborhood cohesion, trust, norms of reciprocity, and social participation. (Published Abstract)