Background: Continuous positive airway pressure (CPAP) is the standard treatment for obstructive sleep apnea (OSA). Our objective was to assess CPAP compliance for active military patients and identify predictors for poor compliance. Methods: A one-site descriptive, retrospective, cross-sectional study of active military patients followed for moderate to severe OSA; and treated with long-term CPAP (2013-2018). The CPAP indications have been validated by the military health army. Results: Fifty-one patients were included (100% male). The mean age was 42.7 ± 9.1 years. The main comorbidities included obesity, hypertension, and diabetes. Forty-two patients (82%) had severe OSA, and 9 patients had moderate OSA associated with severe comorbidity. The mean use of CPAP was 4.1 ±1.6 years. Fixed pressure mode was prescribed in 98% of patients. Twenty-four patients (47 %) reported at least one adverse event during follow-up. At the date point, 36 patients (70%) were still using CPAP. The remaining 15 patients (30%) discontinued CPAP ( 14 ± 5 months). The main reasons for the interruption were resistance to dry nose medicine and intolerance to masks. Of the others, 6 (17%) were not compliant. The major causes of non-compliance were nasal obstruction, mask leakage, and suffocation. Predictive factors of good compliance with CPAP were: the place of residence, the severity of initial excessive daytime drowsiness,  initial AHI, higher effective pressure, clinical efficacy,  and lesser adverse effects of CPAP. Conclusion: The constraints experienced by patients with the device and the severity of the OSA influence adherence to therapy.