A vascular prosthesis for a blood vessel of a patient, which has the following: a hollow-cylindrical main body with a longitudinal axis (L), a proximal opening and a distal opening , and also a main lumen extending between the proximal opening and the distal opening , the main body having a proximal end region and a distal end region , which respectively comprise the proximal opening or the distal opening , and also an intermediate region arranged between the proximal end region and the distal end region , a plurality of stent rings , which are not connected to one another, which are arranged spaced apart one behind the other in the longitudinal direction of the vascular prosthesis and running around in a meandering formation, the stent rings respectively having ogives and webs connecting them, a prosthesis material , to which the stent rings are attached, at least four side branches , which extend distally into the main lumen from fenestrations in the prosthesis material lying between the stent rings , wherein each side branch has a first side-branch opening and a second side-branch opening and also a side-branch lumen extending between the first side-branch opening and the second side-branch opening , the first side-branch opening respectively being firmly attached to the prosthesis material , respectively, via a fenestration , such, that a side-branch attachment is formed; characterized in that the vascular prosthesis has four side branches , which extend into the main lumen , and are arranged in the intermediate region , the intermediate region having a smaller diameter d2 in comparison with the diameters d1, d3 of the end regions . a hollow-cylindrical main body with a longitudinal axis (L), a proximal opening and a distal opening , and also a main lumen extending between the proximal opening and the distal opening , the main body having a proximal end region and a distal end region , which respectively comprise the proximal opening or the distal opening , and also an intermediate region arranged between the proximal end region and the distal end region , a plurality of stent rings , which are not connected to one another, which are arranged spaced apart one behind the other in the longitudinal direction of the vascular prosthesis and running around in a meandering formation, the stent rings respectively having ogives and webs connecting them, a prosthesis material , to which the stent rings are attached, at least four side branches , which extend distally into the main lumen from fenestrations in the prosthesis material lying between the stent rings , wherein each side branch has a first side-branch opening and a second side-branch opening and also a side-branch lumen extending between the first side-branch opening and the second side-branch opening , the first side-branch opening respectively being firmly attached to the prosthesis material , respectively, via a fenestration , such, that a side-branch attachment is formed; characterized in that the vascular prosthesis has four side branches , which extend into the main lumen , and are arranged in the intermediate region , the intermediate region having a smaller diameter d2 in comparison with the diameters d1, d3 of the end regions . <EOS>