The predictive ability of the CHADS₂ index to stratify stroke risk may be mechanistically linked to severity of left atrial (LA) dysfunction. This study investigated the association between the CHADS₂ score and LA function. We performed resting transthoracic echocardiography in 970 patients with stable coronary heart disease and normal ejection fraction and calculated baseline LA functional index (LAFI) using a validated formula: (LA emptying fraction × left ventricular outflow tract velocity time integral)/LA end-systolic volume indexed to body surface area. We performed regression analyses to evaluate the association between risk scores and LAFI. Among 970 subjects, mean CHADS₂ was 1.7 ± 1.2. Mean LAFI decreased across tertiles of CHADS₂ (42.8 ± 18.1, 37.8 ± 19.1, 36.7 ± 19.4, p <0.001). After adjustment for age, sex, race, systolic blood pressure, hyperlipidemia, myocardial infarction, revascularization, body mass index, smoking, and alcohol use, high CHADS₂ remained associated with the lowest quartile of LAFI (odds ratio 2.34, p = 0.001). In multivariable analysis of component co-morbidities, heart failure, age, and creatinine clearance <60 ml/min were strongly associated with LA dysfunction. For every point increase in CHADS₂, the LAFI decreased by 4.0%. Secondary analyses using CHA₂DS₂-VASc and R₂CHADS₂ scores replicated these results. Findings were consistent when excluding patients with baseline atrial fibrillation. In conclusion, CHADS₂, CHA₂DS₂-VASc, and R₂CHADS₂ scores are associated with LA dysfunction, even in patients without baseline atrial fibrillation. These findings merit further study to determine the role of LA dysfunction in cardioembolic stroke and the value of LAFI for risk stratification.