Objective To investigate the changes of blood pressure (BP) on patients with obstructive sleep apnea/hypopnea syndrome (OSA) before and after upper airway surgery. Design Case series with chart review. Setting Tertiary academic medical center. Subjects and Methods Patients with OSA who underwent upper airway surgery were enrolled. We retrospectively investigated the nighttime and daytime BP before and at least 3 months after OSA surgery. Paired t test was used to compare the changes of BP before and after surgery. Generalized estimating equation was used to examine the prognostic significance of the variables in predicting the changes of postoperative BP. Results In total, 176 patients with OSA (149 men, 27 women; mean age, 42.9 years; mean apnea/hypopnea index, 43.1/h) were enrolled in this study. The overall nighttime and daytime BP decreased significantly before and after OSA surgery (daytime systolic BP was reduced from 137.3 ± 14.0 mm Hg to 132.7 ± 17.0 mm Hg, P < .01; nighttime systolic BP was reduced from 138.7 ± 16.0 mm Hg to 133.7 ± 15.3 mm Hg, P < .01; daytime diastolic BP was reduced from 87.7 ± 14.7 mm Hg to 84.9 ± 10.6 mm Hg, P = .01; nighttime diastolic BP was reduced from 85.4 ± 12.9 mm Hg to 83.1 ± 11.1 mm Hg, P = .02). The changes of nighttime systolic and diastolic BP were significantly associated with the improvement of percentage of O2 saturation <90% during polysomnography. Conclusion Surgical modifications of the upper airways for patients with OSA could benefit blood pressure.