OBJECTIVE: To evaluate the predictive value of Holter ECG recordings for patients with moderate-severe obstructive sleep apnea and hypopnea syndrome (OSAHS). METHODS: Holter recordings was performed in 76 patients who were diagnosed OSAHS by polysomnography (PSG) within one month from Jan. 2008 to July 2009 in our hospital. Twenty-eight patients were identified as mild OSAHS (AHI < or = 20) and forty-eight patients were moderate-to-severe OSAHS (AHI > 20). The indexes of heart rate variability (HRV), total scores of thirteen sleep apnea risk indexes of Holter recordings and BMI were analyzed by bivariate Logistic regression analysis. RESULTS: Clinical features (eg. Gender, age, complicated with hypertension, coronary heart disease, diabetes mellitus, hyperglycemia, and taken beta-blocker), total scores, the sum of thirteen sleep apnea risk scores collected by Holter recordings (5.64 + or - 2.33 vs. 6.42 + or - 2.22, respectively, P > 0.05) were similar between patients with mild OSAHS and moderate-to-severity OSAHS. VLF/Total Power > 70%, the difference of daytime/nighttime LF Power < -70 and BMI were independent predictors of moderate-to-severe OSAHS with OR 3.98 (1.087 - 14.596), 3.69 (1.106 - 12.285) and 1.28 (1.062 - 1.544), respectively (all P < 0.05). CONCLUSIONS: VLF/Total Power and the difference of daytime/nighttime LF Power and BMI could be used as screening parameters to recognize patients with moderate-to-severe OSAHS.