We examined in a longitudinal study whether dispositional optimism (as measured by the Life Orientation Test) predicts success in making health changes associated with lower risk of coronary heart disease. Subjects were 22 patients participating in an 18 week cardiac rehabilitation program. As part of the program all patients were assigned goals (e.g., reduce weight by 20 lbs) designed to decrease the risk of a cardiac event. Optimism measured at the outset of the program was associated with greater success in achieving lower levels of saturated fat, body fat, and global coronary risk, and with greater success in increasing aerobic capacity by the end of the program. Moreover, these effects were significant after controlling for the magnitude of the goal, the number of health changes, and negative affect.