Objective To evaluate the influence of nuclear factor (NF)-κB activation in peripheral blood mononuclear cells (PBMCs) on vascular inflammation in elderly patients with obstructive sleep apnea-hypopnea syndrome (OSAHS). Methods The 40 elderly subjects (≥65years old) were classed into control, mild, moderate and severe groups (n = 10, respectively)according to polysomnography (PSG). After PSG, the samples of peripheral venous blood were collected, and PBMCs were isolated. Nuclear protein was extracted and NF-κB was measured by Western blotting. ELISA was applied to measure the levels of TNF-α and IL-6 in serum. Blood samples from 10 cases (moderate 5 and severe 5) were measured again after four weeks of continuous positive airway pressure (CPAP) treatment. Results The expression of NF-κB in PBMCs and the concentration of TNF-α in serum were significantly increased in severe and moderate OSAHS patients compared with controls (P＜0. 05). The NF-κB expression was positively correlated with AHI (r=0. 617, P＜ 0. 001) and TNF-α concentration (r = 0. 498, P＜ 0. 001 ), negatively correlated with LSaO2 (r= -0. 548, P＜0. 001), and not correlated with IL-6 concentration (r=0. 365, P=0. 201).The CPAP treatment could significantly inhibit NF-κB activation in PBMCs and reduce TNF-αexcretion (P＜0.05, respectively). Conclusions PBMCs may play an important role in vascular endothelial injury through NF-κB expression and TNF-α excretion in elderly OSAHS patients, which is closely associated with the severity of the syndrome and night hypoxemia. CPAP treatment can inhibit the pathophysiologic process effectively.