Abstract The search for an ideal vascular prosthesis to bypass peripheral vascular obstructive lesions is necessary where autologous tissues are either unavailable or unsuitable. This paper will outline the development and use of vascular conduits, principally of biological origin. The clinical benefits and limitations of these materials are discussed. The development of a composite biosynthetic prosthesis (Omniflow™) is described, together with the testing methods used to determine and predict its suitability for use as an arterial substitute. The ovine biosynthetic prosthesis has significantly improved surface and mural properties over previous attempts at producing prostheses for vascular reconstruction. Immunohistological studies on samples recovered from dogs after 4 years show that the original ovine collagen is still present after 4 years, and it is further augmented by the deposition of new, host-derived connective tissue.