A prosthetic aortic conduit for replacing a root portion of an aorta is provided. The conduit comprises a continuous tubular conduit along a substantially common axis. A portion of the tubular conduit does not substantially deform in a longitudinal direction and has resilient means which allow said another portion of the conduit to be expandable in a lateral direction. The portion that is able to deform laterally mimics the function of the sinuses of Valsalva. The method of manufacturing such a conduit comprises the steps of having a continuous weave of rows of yarn or the equivalent with a change in tightness of the rows so that in some portion of the conduit it is expandable in the lateral direction and in some portion of the conduit it is expandable in the longitudinal direction.