The character and essence of changes taking place in the connective tissue matrix of the vascular wall under the effect of thymus deficiency are not well enough clarified. The aim of the study was to assess the content of collagen, elastin, total glucosamines, total glycoproteins, total nonfibrillar protein and total protein in the aorta total glycoproteins, total nonfibrillar protein and total protein in the aorta of adult thymectomized rats of the Wistar strain and in control animals over a 12-month post-thymectomy period. The amount of collagen and elastin augments both in connection with the aging process (after 2-4 months), and as a result of thymectomy. Glycoproteins show an increase starting from the third month in the controls, and from the fifth month in thymectomized animals. Glucosamines display a fluctuating decrease parallel to aging in either of the groups under study. The content of total protein and nonfibrillar protein reveals no differences worthy of notice. It is reasonable to assume the existence of a correlation between thymus activity and metabolism of the connective tissue components in the vascular wall of rats.