Background: Aortic dissection is a life-threatening manifestation of Marfan's syndrome. Preliminary evidence suggests that obstructive sleep apnea (OSA) is associated with aortic disease in Marfan's syndrome. Objectives: To study the effect of OSA on aortic events in Marfan's syndrome. Methods: In patients with Marfan's syndrome, a sleep study was performed at baseline and OSA was defined as >5 events of apnea/hypopnea (A+H) per hour in bed. Operation because of progressive aortic dilatation and death because of aortic rupture were defined as 'aortic events'. Kaplan-Meier survival analyses were used to compare event-free survival in patients with and without OSA. Cox regression models were used to explore the effects of covariates on event-free survival. Results: Data from 44 patients (mean age 37.4 years, 30 females) were available for analysis; 15 patients (34.1%) had OSA. The median follow-up time was 29 (interquartile range 24-36) months. Five patients had an aortic event within the follow-up time. Median event-free survival was 51.6 months. Event-free survival was significantly shorter in patients with OSA compared to patients without OSA (p = 0.012). In univariate analysis, A+H was associated with aortic events [hazard ratio (HR) 1.09, 95% confidence interval (CI) 1.01-1.18, p = 0.023]. Taking the interaction between BMI and A+H into account increased the HR for A+H (HR 1.75, 95% CI 1.003-3.048, p = 0.049). This association was no longer significant when other covariates were forced into the multivariate analysis. Conclusions: These data suggest that aortic event-free survival may be shorter in patients with Marfan's syndrome and OSA compared to patients without OSA, but more data from well-designed studies are needed to prove this association.