Modern data on types, physico-chemical properties, physiological role of copper-containing amine oxidase of blood vessels are reviewed. Properties of lysyl oxidase--specific copper-containing amine oxidase--are described. Importance of the enzyme for normal functions of connective tissue as well as alterations in the enzymatic activity under various pathological conditions are discussed. At the same time, properties and physiological functions of another copper-containing amine oxidase of blood vessels, which uses polyamines as substrate, are considered. Effect of the copper levels on content of polyamines in body is discussed.