A method of making a bidirectional branch within an endoluminal prosthesis, the method comprising: laying a tubular segment of graft material flat, the tubular segment of graft material comprising a first lateral edge, a second lateral edge, a width extending from the first lateral edge to the second lateral edge, and a length extending from a proximal end to a distal end of the tubular segment; partitioning the tubular segment into first and second sections (32, 34) along the length of the tubular segment, wherein the first section extends from the first lateral edge toward the second lateral edge and comprises a width less than the width of the tubular segment, and wherein the second section extends from the second lateral edge toward the first lateral edge and comprises a width less than the width of the first section such that a total width of the first and second sections (32, 34) is the same as the width of the tubular segment; partitioning the second section of the tubular segment into at least three sub-sections (34a-34e), a first sub-section (34a, 34b) extending from the proximal end toward the distal end for a length, a second sub-section extending from the first sub-section (34a, 34b) toward the distal end for a length, and a third sub-section (34d, 34e) extending from the second sub-section to the distal end and has a length; wherein a total length of the three sub-sections (34a-34e) is the same as the length of the tubular segment; connecting the tubular segment along a lateral edge of the first sub-section (34a, 34b) from the proximal end to the second sub-section and along a lateral edge of the third sub-section (34e, 34e) from the distal end to the second sub-section, wherein the lateral edges of the first and third sub-sections (34a, 34b, 34d, 34e) are opposite the second lateral edge of the tubular segment; and turning the tubular segment inside out such that the first, second and third sub-sections of the second section form the bidirectional branch, the bidirectional branch is positioned within a lumen of the endoluminal prosthesis and an opening of the second sub-section is exposed. laying a tubular segment of graft material flat, the tubular segment of graft material comprising a first lateral edge, a second lateral edge, a width extending from the first lateral edge to the second lateral edge, and a length extending from a proximal end to a distal end of the tubular segment; partitioning the tubular segment into first and second sections (32, 34) along the length of the tubular segment, wherein the first section extends from the first lateral edge toward the second lateral edge and comprises a width less than the width of the tubular segment, and wherein the second section extends from the second lateral edge toward the first lateral edge and comprises a width less than the width of the first section such that a total width of the first and second sections (32, 34) is the same as the width of the tubular segment; partitioning the second section of the tubular segment into at least three sub-sections (34a-34e), a first sub-section (34a, 34b) extending from the proximal end toward the distal end for a length, a second sub-section extending from the first sub-section (34a, 34b) toward the distal end for a length, and a third sub-section (34d, 34e) extending from the second sub-section to the distal end and has a length; wherein a total length of the three sub-sections (34a-34e) is the same as the length of the tubular segment; connecting the tubular segment along a lateral edge of the first sub-section (34a, 34b) from the proximal end to the second sub-section and along a lateral edge of the third sub-section (34e, 34e) from the distal end to the second sub-section, wherein the lateral edges of the first and third sub-sections (34a, 34b, 34d, 34e) are opposite the second lateral edge of the tubular segment; and turning the tubular segment inside out such that the first, second and third sub-sections of the second section form the bidirectional branch, the bidirectional branch is positioned within a lumen of the endoluminal prosthesis and an opening of the second sub-section is exposed.