The perception of health risks and risky health behaviors are closely associated. In this paper, we investigate the accuracy of health risk perceptions among obese individuals, aged 50-62 years. We compare subjective risk perceptions for various diseases elicited in the American Life Panel to individual's objective risks of the same diseases. We find that obese individuals significantly underestimate their 5-year risks of arthritis or rheumatism and hypertension, whereas they systematically overestimate their 5-year risks of a heart attack and a stroke. Obese individuals are thus aware of some but not all obesity-related health risks. For given diseases, we document substantial heterogeneities in the accuracy of expectations across individuals.