This study assessed the contextual and individual effects of social trust on health. Methods consisted of a multilevel regression analysis of self-rated poor health among 21,456 individuals nested within 40 US communities included in the 2000 Social Capital Community Benchmark Survey. Controlling for demographic covariates, a strong income and education gradient was observed for self-rated health. Higher levels of community social trust were associated with a lower probability of reporting poor health. Individual demographic and socioeconomic predictors did not explain the association of community social trust with self-rated health. Controlling for individual trust perception, however, rendered the main effect of community social trust statistically insignificant, but a complex interaction effect was observed, such that the health-promoting effect of community social trust was significantly greater for high-trust individuals. For low-trust individuals, the effect of community social trust on self-rated health was the opposite. Using the latest data available on community social trust, we conclude that the role of community social trust in explaining average population health achievements and health inequalities is complex and is contingent on individual perceptions of social trust. Future multilevel investigations of social capital and population health should routinely consider the cross-level nature of community or neighborhood effects.