['Unrealistic optimism-typically conceptualized as underestimation of comparative risk-has been previously associated with poorer health behaviors and outcomes, but no research to date has examined the association between unrealistic optimism and subclinical or clinical disease endpoints. Here, cross-sectional data from one time point in the Pittsburgh Healthy Heart study are used to examine whether unrealistic optimism about risk of heart disease is associated with carotid artery intima-media thickness (IMT), a subclinical marker of atherosclerosis.', 'Participants were 148 adults aged 57-77. Objective risk score was calculated using the Framingham calculator, and IMT was regressed on risk score and perceived risk. Controlling for the Framingham risk score effectively equated risk across the sample, meaning that lower risk perceptions represented unrealistic optimism.', 'When controlling for the risk score, risk perceptions were negatively associated with IMT (β = -.21, p < .01, t = -2.79, d = .46), a finding that was not moderated by gender. The risk score was also associated with IMT (β = .42, p < .001, t = 5.55, d = .91).'] Is unrealistic optimism associated with subclinical atherosclerosis?