Abstract: Objective To investigate the long-term efficacy of continuous positive airway pressure (CPAP)treatment for the elderly with obstructive sleep apnea syndrome (OSAS). Methods Case control study was performed among 106 elderly with obstructive sleep apnea syndrome (OSAS). They were divided into treatment group (n =34) and control group (n = 72), based on whether they underwent long-term CPAP treatment or not. The long-term efficacy of CPAP treatment was evaluated by long-term clinical observation. Results The incidence of cardiovascular events was 12%(4/34) in treatment group and 47%(34/72) in control group (P <0. 01). Kaplan-Meier survival analysis showed that after controlling the factors of age, sex, body mass index, apnea hypopnea index and previous diseases, failing to receive CPAP treatment was the independent risk factor for cardiovascular events (χ2 = 17.0, P < 0.01). Conclusions CPAP treatment for moderate - severe OSAS could reduce cardiovascular and neurovascular events risk for elderly patients with OSAS.