Aim — to analyze the results of aortic valve reimplantation, data of histological examination of aortic root and ascending aorta wall in patients with proximal aortic dilatation less than 50 mm.  Material and methods. From August 2010 to December 2013 David’s surgery was carried out in 15 patients with aortic root and ascending aorta dilatation up to 50 mm and aortic insufficiency. All patients had severe circulatory failure. Proper sizes of aortic root for each patient were obtained by indexing to the body surface area (fibrous ring, sinuses of Valsalva, sino-tubular junction, ascending aorta). Histological survey was carried out by express and planned research. Results. Significant preoperative aortic valve regurgitation with intact leaflets but enlarged aortic root at all measured levels was observed. Express and planned histological results revealed significant aortic wall pathology. All patients were discharged, complete recovery of the aortic valve function, positive dynamics of left ventricular remodeling were achieved.