We examined the postoperative clinical results and hemodynamic performance of full root replacement using a freestyle stentless bioprosthesis performed in patients with severe aortic stenosis or aortic root disease. We performed 17 full root replacements with a stentless bioprosthesis. The mean age of the patients was 73.9 +/- 4.1 years, ranging from 63 to 81, and 35% were male. The operative indications were aortic stenosis (AS) in 9 patients, aortic stenosis with regurgitation (ASR) in 4, and aortic regurgitation due to aortic root dissection or annuloaortic ectasia in 4. The valve size of the freestyle bioprosthesis was 25.1 +/- 2.6 mm, ranging from 21 to 29 mm. There were no early or late mortalities. No postoperative aortic regurgitation was found. In the 13 patients undergoing an operation for AS or ASR, peak pressure gradients were 8.5 +/- 4.2 and 8.4 +/- 5.2 mmHg, and LV mass indices were 159.4 +/- 19.0 and 106.9 +/- 22.6 g/m(2), as determined by echocardiography at 1 and 10 months after operation, respectively. Full root replacement with stentless bioprosthesis is a suitable procedure for patients of advanced age with severe AS, aortic root dissection, or annuloaortic ectasia, because of its superior hemodynamics.