Abstract: A significant proportion of patients may require the continued use of positive airway pressure (PAP) following upper airway surgery. The objective of this study is to determine whether site-specific surgical modification of upper airway improved tolerance to PAP treatment in those patients who continued to use PAP following surgery. Medical records of patients who underwent site-specific surgical modification of upper airway were identified on retrospective chart review. Of the 45 patients who had both preoperative and postoperative sleep studies and were successfully contacted, only 16 patients used PAP prior to the surgery and continued to use it following the surgery. Preoperative and postoperative AHI, lowest oxygen saturation, ESS, PAP pressure, PAP tolerability, number of hours per night of PAP use, and BMI were retrieved from medical records as well as phone interviews. Statistical analysis was performed using paired-samples t-tests in these 16 patients. Most of the 16 patients who continued to use PAP following the surgery did not “respond” to surgical treatment even though there was a statistically significant drop in AHI (p=0.027). Only 3 patients in this group were considered “responders” but they chose to continue the use of PAP because they continue to derive benefit from its use. Majority of these patients underwent UPPP in conjunction with some types of base of tongue procedure(s). Following surgery, statistically significant improvement in PAP tolerance (p=0.003), increased PAP use (p=0.015) and decrease in titrated PAP pressure (p=0.013) were noted. We found in this study that tolerance and compliance of PAP improved following site-specific upper airway surgery.