This invention relates generally to an endoluminal prosthesis, and more particularly, to a stent graft assembly and method for treating branched vessels. The assembly comprises a first prosthesis having an overall shortened length comprising a main body (4) formed of biocompatible graft material having a tapered proximal end (6). A bifurcated portion extends distally from the main body. The bifurcated portion comprises a first tubular portion (18) defining a first lumen (26) and a second tubular portion (20) defining a second lumen (34). The assembly further comprises a second prosthesis having a tubular body (60) of biocompatible graft material with a flared distal end portion (68). The flared distal end portion of the second prosthesis is configured to sealingly engage with the tapered main body of the first prosthesis.
