Today's healthcare environment demands objective assessment of surgical outcomes. The recent otolaryngologic literature has established acoustic rhinometry (AR) as a valid instrument to objectively document nasal patency. The purpose of this article is to evaluate the utility of AR in predicting outcomes after sinonasal surgery. All patients scheduled for sinonasal surgery at the Tulane University and University of Mainz Departments of Otolaryngology between 10/1/98 and 12/15/98 were enrolled. All subjects underwent AR and completed a sinonasal outcome survey (SNOT-20) one day before and two months after their surgical procedure. Thirty-one patients were enrolled. The SNOT-20 raw scores improved from a mean of 7.93 (+/- 3.78) preoperatively to 3.35 (+/- 2.33) postoperatively (p < 0.05). The I-notch revealed no significant change postoperatively. The mean bilateral predecongestion C-notch increased from 1.257 cm2 to 1.451 cm2 (p < 0.05). Patients with a bilateral C-notch > 1 cm2 were 1.96 times more likely to have a five-point improvement in the SNOT-20 raw score (95% CI = 1.17, 3.27). The mean value of the C-notch is significantly altered (increased) as a result of sinonasal surgery. Patients with a preoperative cross-sectional area < 1 cm2 are less likely to report large postoperative subjective improvement. These results indicate that patients with poor geometry at the area of the C-notch do not fare as well surgically as those with better preoperative measurements.