Interatrial block (IAB) is associated with a multitude of medical conditions. The aim of this retrospective study was to investigate whether CHADS(2) (congestive heart failure, hypertension, age >= 75 years, diabetes mellitus, prior stroke) score is positively associated with the development of IAB. A total of 1072 patients (men, 555; women, 517; mean age, 61 +/- 14 years) were included in the study. P-wave duration was measured manually using a caliper. IAB was defined as a P-wave duration of >= 120 ms on a 12-lead electrocardiogram. CHADS(2) scores were calculated retrospectively. Among the 1072 patients, the prevalence of IAB was 36.1% (387/1072). In multivariate analysis, increased CHADS(2) score (odds ratio [OR]. 1.810; 95% confidence interval [CI], 1.577-2.077; P < 0.001), coronary artery disease (OR, 1.536; 95% CI, 1.065-2.216; P = 0.022), and increased left atrial diameter (OR, 1.039; 95% CI, 1.008-1.071; P = 0.013) were independently associated with IAB. The percentages of patients with IAB among those with a CHADS(2) score of 0, 1, 2, 3, 4, 5, and 6 were 20.6%, 33.0%, 45.0%, 55.9%, 61.9%, 77.8%, and 100%, respectively (P < 0.001). There was a greater percentage of patients with a CHADS(2) score of >= 2 with IAB compared with a CHADS(2) score of < 2 (26.5% vsrsus 52.0%; P < 0.001). In receiver operating curve (ROC) analysis, CHADS(2) score (area under the curve, 0.670; 95% CI, 0.636-0.704: P < 0.001) was predictive of IAB. In conclusion. CIIADS(2) score was significantly associated with the development of JAR in this study population.