Obstructive sleep apnea (OSA) is a sleep disorder associated with significant cardiovascular comorbidities, including cardiac arrhythmia. The STOP-BANG questionnaire is an eight-item self-report questionnaire designed to screen patients for OSA and was validated in preoperative surgical patients. The STOP items are snoring, daytime tiredness, observed apneas and high blood pressure. The BANG items are body mass index >35 kg/m2, age >50 years, neck circumference >40 cm and male gender. We aimed to determine the screening properties of the STOP-BANG questionnaire in patients with arrhythmia. Non-selected consecutive patients were recruited from arrhythmia clinics. Patients with previously diagnosed and/or treated OSA were excluded. The STOP-BANG questionnaire was self-administered. Patients underwent two consecutive nights of home sleep recording. OSA was defined as an apnea-hypopnea index score of ≥5/hr of sleep. The screening properties of the STOP-BANG questionnaire were analysed compared with the objective diagnosis of OSA by ambulatory testing. Ninety-five patients were included in the final analysis. Eighty-five percent were found to have OSA. The STOP-BANG score of ≥3 was 89% sensitive and 36% specific for diagnosis of OSA. The STOP-BANG questionnaire had fair performance, as indicated by an area under the curve of 0.74 (p = .004). In conclusion, the STOP-BANG questionnaire is sensitive; however, it has a low specificity with a high false positive rate. Given that a large number of atrial fibrillation patients need testing for OSA, we recommend the use of a level II sleep study regardless of the results of the screening questionnaire. This approach accurately identifies OSA and may limit the cost of unnecessary level-I sleep studies.