BACKGROUND: Obstructive sleep apnea (OSA) is a known risk factor for atrial fibrillation (AF). However, it remains unclear whether OSA is independently associated with worse cardiovascular and neurological outcomes in patients with AF. METHODS: We used the ORBIT-AF I and ORBIT-AF II to conduct a retrospective cohort study of 22,760 patients with AF with and without OSA. Adjusted multivariable Cox proportional hazards models was used to determine whether OSA was associated with increased risk for major adverse cardiac and neurologic events (MACNEs) (cardiovascular death, myocardial infarction, stroke/transient ischemic attack/non-central nervous system embolism (stroke/SE), and new-onset heart failure], combined and individually. RESULTS: A total of 4,045 (17.8%) patients had OSA at baseline. Median follow-up time was 1.5 (interquartile range: 1-2.2) years, and 1,895 patients experienced a MACNE. OSA patients were younger (median [interquartile range] 68 [61-75] years vs 74 [66-81] years), were more likely male (70.7% vs 55.3%), and had increased body mass index (median 34.6 kg/m2 [29.8-40.2] vs 28.7 kg/m2 [25.2-33.0]). Those with OSA had a higher prevalence of concomitant comorbidities such as diabetes, chronic obstructive pulmonary disease, and heart failure. OSA patients had higher use of antithrombotic therapy. After adjustment, the presence of OSA was significantly associated with MACNE (hazard ratio: 1.16 [95% CI: 1.03-1.31], P = .011). OSA was also an independent risk factor for stroke/SE beyond the CHA2DS2-VASc risk factors (HR: 1.38 [95% CI 1.12-1.70], P = .003) but not cardiovascular death, myocardial infarction, new-onset heart failure, or major bleeding. CONCLUSIONS: Among patients with AF, OSA is an independent risk factor for MACNE and, more specifically, stroke/SE.