Background: The incidence of morbid obesity is increasing and has led to an increase in bariatric procedures and previous studies have shown that 71% of these patients suffer from obstructive sleep apnea (OSA). Patients with OSA have a higher rate of postoperative complications. We investigated if patients with OSA undergoing laparoscopic gastric bypass surgery have an increased risk of postoperative respiratory events. In this observational study we examined the data of 89 consecutive patients undergoing gastric bypass surgery.Methods: All patients scheduled for gastric bypass surgery between 7/28/2010 and 02/15/2011 were enrolled and managed according to our routine clinical protocol (48 with OSA / 41 without OSA (NOSA)). Depending on the patient’s preoperative compliance with CPAP therapy, they were further assigned into a compliant (OSAc) and noncompliant (OSAn) group. A respiratory event was defined as a deviation from the regular postoperative management.Results: Both OSA and NOSA groups were similar based on clinical characteristics and narcotic consumption. Fourteen patients (29.2%) suffered from a respiratory event in the OSA group and 8 patients (19.5%) in the NOSA group (p=0.29). Patients compliant with continuous positive airway pressure CPAP had a similar complication rate to patients without OSA (p=0.96). 53.8% of patients with OSA that were noncompliant with CPAP therapy (OSAn) had a respiratory event in the direct postoperative period. This is statistically significant in comparison to patients diagnosed with OSA that are compliant with CPAP (OSAc) (p=0.03)Conclusion: It may be beneficial to encourage OSA patients to use CPAP preoperatively to reduce postoperative respiratory events. Furthermore, adequately treated OSA may not be an independent risk factor for postoperative respiratory events.