BACKGROUND: Few longitudinal studies have delineated the association between traditional cardiovascular risk factors and development of aortic stenosis (AS). OBJECTIVES: The authors examined the association between traditional cardiovascular risk factors and incident severe AS in a large, unselected elderly population. METHODS: This observational cohort study used multiple linked health care population-based databases of individuals older than 65 years on April 1, 2002, without prior valvular disease, coronary artery disease, heart failure, cardiac arrhythmia, cerebrovascular disease, congenital heart disease, or admissions with cardiac symptoms. The relationship between hypertension (HTN), diabetes, dyslipidemia, and incident severe AS requiring hospitalization or surgical or interventional treatment was examined. RESULTS: Among 1.12 million individuals followed for a median of 13 years, 20,995 subjects developed severe AS. Overall absolute incidence was 144 per 100,000 person-years (169 and 127 per 100,000 person-years in men and women, respectively). In cause-specific hazard models, HTN (adjusted hazard ratio [HR]: 1.71; 95% confidence interval [CI]: 1.66 to 1.76), diabetes (HR: 1.49; 95% CI: 1.44 to 1.54), and dyslipidemia (HR: 1.17; 95% CI: 1.14 to 1.21) were all significantly associated with increased risk of developing severe AS (all p < 0.001). There was a positive dose-response relationship between the number and duration of cardiac risk factors and risk of AS. In the Fine-Gray model, all 3 risk factors were independently associated with a higher incidence of AS. The population-attributable risk of AS associated with 3 cardiac risk factors was 34.4% (95% CI: 32.8 to 36.0). CONCLUSIONS: HTN, diabetes, and dyslipidemia have independent and dose-response associations with incident AS in an unselected population of older individuals, and together accounted for approximately one-third of the incidence of severe AS.