BACKGROUND AND PURPOSE: The association between optimism and pessimism and health outcomes has attracted increasing research interest. To date, the association between these psychological variables and risk of stroke remains unclear. We examined the relationship between pessimism and the 7-year incidence of stroke. METHODS: A random sample of 23 216 adults (9480 men, 13 796 women) aged 20 to 54 years completed the pessimism scale in 1998, that is, at study baseline. Fatal and first nonfatal stroke events during a mean follow-up of 7.0 years were documented by linkage to the national hospital discharge and mortality registers leading to 105 events. RESULTS: Unadjusted hazard ratio was 0.44 (95% CI, 0.25 to 0.77) for participants in the lowest quartile (a low pessimism level) when compared with those in the highest quartile (a high pessimism level). After serial adjustments for sociodemographic characteristics, cardiovascular biobehavioral risk factors, depression, general feeling of stressfulness, and ischemic heart disease, the fully adjusted hazard ratio was 0.52 (95% CI, 0.29 to 0.93). CONCLUSIONS: In this population of adult men and women, low level of pessimism had a robust association with reduced incidence of stroke.