Abstract: The present invention provides modular bifurcated intraluminal tubular prostheses, particularly stents and stent-grafts, for the treatment of disease conditions, particularly aneurysms. Modular sections of the prostheses, or “prosthetic modules,” may be selectively assembled to form a prosthesis having characteristics which are tailored to the specific requirements of the patient, including branch angle and branch lumen sizes which match the patients vascular geometry. A Y-connector prosthetic module structure provides support and separation for each of the adjacent branching lumens. Radiopaque markers on the prostheses promote alignment between prosthetic modules and with the body lumen system.