Background. Citizens of the United States are less likely than are citizens of Europe and several non-European nations to believe that humans evolved from an earlier species. Several theories have been proposed to explain Americans' disbelief in human evolution, but empirical investigation has been sparse.

 Methods. Data on belief in evolution, on scientific knowledge unrelated to evolution, on socioeconomic status, on Christian religiosity, and on political polarity were identified in the General Social Surveys (GSSs) for 1993, 1994, and 2000. These data were then analyzed in bivariate and multivariate tests of theories about evolutionary and anti-evolutionary views.

 Findings. Christian religiosity was the strongest correlate of disbelief in evolution. Low educational attainment was another positive, but weaker, correlate, though disbelief in evolution was not related to general measures of scientific knowledge. Political liberalism and political conservatism predicted evolutionary belief even after controlling for religiosity, education, and other potential confounders. Subcultural differences in belief — those between blacks and whites, rural dwellers and urban dwellers, Southerners and non-Southerners, dogmatists and non-dogmatists — became insignificant under appropriate controls.

 Conclusion. Christian religiosity, especially in a fundamentalist variety, was the primary correlate of disbelief in evolution. Lack of education was an important but lesser factor. Independent of religiosity and education, political conservatism predicted disbelief.