A robust and very persistent association between indicators of socioeconomic status (SES) and the onset of life-threatening disease is a prominent concern of medical sociology. The persistence of the association over time and its generality across very different places suggests that no fixed set of intervening risk and protective factors can account for the connection. Instead, fundamental-cause theory views SES-related resources of knowledge, money, power prestige, and beneficial social connections as flexible resources that allow people to avoid risks and adopt protective strategies no matter what the risk and protective factors are in a given place or time. Recently, however, intelligence has been proposed as an alternative flexible resource that could fully account for the association between SES and health and thereby find its place as the epidemiologists' “elusive fundamental cause” (Gottfredson 2004). We examine the direct effects of intelligence test scores and adult SES in two data sets containing measures of intelligence, SES, and health. In analyses of prospective data from both the Wisconsin Longitudinal Study and the Health and Retirement Survey, we find little evidence of a direct effect of intelligence on health once adult education and income are held constant. In contrast, the significant effects of education and income on health change very little when intelligence is controlled. Although data limitations do not allow a definitive resolution of the issue, this evidence is inconsistent with the claim that intelligence is the elusive fundamental cause of health disparities, and instead supports the idea that the flexible resources people actively use to gain a health advantage are the SES-related resources of knowledge, money, power, prestige, and beneficial social connections.