The interdomal fat pad (IFP) is an important structure related to tip deformity in rhinoplasty. This study aimed to evaluate the IFP by ultrasonography before surgery, and to demonstrate the existence of the IFP as a distinct anatomic structure in cadavers and patients. Three dimensions of the IFP were measured in 23 patients using ultrasound before rhinoplasty and in 10 cadavers using dissection. All fat pads were examined by histopathologic methods. In the cadavers, three dimensions of the IFP were found: 2.3 x 3.7 x 12.8 mm. In the patients, three dimensions of IFP were measured by ultrasonography: 2.8 x 4.1 x 13.7 mm. Histopathologic examinations showed that the IFP is a structure differentiated from subcutaneous tissue. The IFP was demonstrated in all cadavers and patients by surgical and radiologic methods. All cases had a fat pad in the interdomal space with varying sizes.