Research has shown that unrealistically-optimistic people believe that they will experience fewer negative events and more positive events than other persons. This paper analyzes a scale which was designed to measure the several cognitive dimensions underlying unrealistic optimism about health. For this study, 220 college students completed a 12-item scale which was based on factors of illness invincibility, illness apathy, and lifetime illness likelihood. Participants also filled out items from other scales believed to be related to unrealistic optimism about health. Results indicate that health history was important for the subject only; close relatives with a serious illness did not lessen optimism. People with an internal locus of control were the most optimistic, followed by people who believed "powerful others" were in control. Those who believed that chance played the most important role in determining health outcomes revealed the least optimism. The findings suggest that there is cognition beyond mere illness controllability which may underlie an unrealistic optimism about health. If people believe that they will not become ill, they may be less inclined to take healthy precautions. The scale generated for this study is still in its developmental stage. Some changes are recommended to improve the scale's validity. (RJM)