The objective of this study was to measure the effect of a single, preoperative 10 mg dose of dexamethasone on postoperative edema associated with rhinoplasty. This was a randomized, double-blind prospective study conducted in a military academic tertiary referral center. Twenty men, aged 18 to 45 years, were enrolled in the study over 28 months. All 20 men underwent rhinoplasty with osteotomy. Preoperative magnetic resonance imaging scans were obtained on the morning of surgery and postoperative scans were obtained within 48 hours. Postoperative edema was quantified as the difference in soft tissue thickness (mm) between the pre- and postoperative scans. Contrary to our expectations, the rhinoplasty patients who received dexamethasone had increased postoperative edema (p < 0.02) when compared to patients not receiving dexamethasone. This is the first objective, double-blind study that shows an increase in postoperative edema after rhinoplasty with a single preoperative dose of dexamethasone.