Background Psoriasis is associated with cardiovascular morbidity and mortality. However, the association between psoriasis and arrhythmia has not been adequately studied. Objective We sought to investigate whether patients with psoriasis have an increased risk of arrhythmia. Methods This population-based cohort study identified 40,637 patients with psoriasis and 162,548 subjects without psoriasis matched by age, sex, history of coronary artery disease, hypertension, and diabetes in the Taiwan National Health Insurance Research Database during 2004 through 2006. Results After adjusting for medical history and medication use, patients with psoriasis were at increased risk of overall arrhythmia (adjusted hazard ratio [aHR] 1.34; 95% confidence interval [CI] 1.29-1.39). The risks of arrhythmia were higher in all subgroups, including patients with severe (aHR 1.25; 95% CI 1.12-1.39) and mild (aHR 1.35; 95% CI 1.30-1.41) psoriasis, and in patients with (aHR 1.46; 95% CI 1.22-1.74) and without (aHR 1.33; 95% CI 1.28-1.39) psoriatic arthritis. Limitations The National Health Insurance Research Database did not contain information regarding Psoriasis Area and Severity Index, cigarette smoking, or alcohol consumption. Conclusion Patients with psoriasis were at higher risk of developing arrhythmia, particularly for those with psoriatic arthritis, independent of traditional cardiovascular risk factors.