A device for forming an anastomosis of blood vessels or ducts includes a first inner cylindrical element for engaging a corresponding first blood vessel/prosthesis end portion and a first middle cylindrical element into which the first inner cylindrical element is inserted to bend the legs of the first inner cylindrical element inwards to a predetermined extent so that deformable legs thereof engage the vessel/prosthesis wall. The device includes a second inner cylindrical element for engaging a corresponding second blood vessel/prosthesis end portion and a second middle cylindrical element into which the second inner cylindrical element can be inserted to bend the legs of the second inner cylindrical element inwards to a predetermined extent so that deformable legs thereof engage the vessel/prosthesis wall. The device also includes an outer element for reciprocally connecting the first and second middle cylindrical elements.
