Abstract: AIM: To explore the correlation between blood pressure (BP) and heart rate variability (HRV) in elderly patients with obstructive sleep apnea-hypopnea syndrome (OSAHS). METHODS: Included in the study were 41 elderly patients diagnosed with OSAHS (trial group) and 41 elderly snoring patients without OSAHS (control group) by portable polysomnography in our hospital from January 2006 to December 2007. Indexes of BP and HRV of all patients were acquired by Holter and ambulatory blood pressure monitoring. RESULTS: Body mass index, waist circumference and neck circumference in the trial group were significantly higher than those in the control group (P<0.05 or P<0.01). Statistically significant HRV differences were observed between groups in time-domain indexes SDNN, SDNNI, rMSSD and PNN50 as well as frequency-domain indexes TP, LF, HF and LF/HF (P<0.05). Differences of BP variability during day, night, and 24-h systolic and diastolic BP between groups were also statistically significant (P<0.05 or P<0.01). CONCLUSION: HRV of elderly OSAHS patients is significantly abnormal and their BP variability increases significantly, especially at night.