A project was undertaken to develop a computational fluid dynamics (CFD) code for use in nozzle afterbody analysis. Objectives were to create a three-dimensional code capable of calculating afterbody flows with accuracy quantitatively close to the Navier-Stokes solutions, but which would use significantly fewer computer resources. The resulting program coupled an inverse boundary-layer routine with an Euler code and incorporated a jet plume. Calculations were made for the axisymmetric AGARD 15-deg boattail afterbody with variations in nozzle pressure ratio for Mach numbers 0.6 and 0.9, and compared with experimental results. The code predicted drag changes with NPR which showed the proper variations, but the code did not provide the accuracy required for typical nozzle afterbody analysis. (NPR = Nozzle total pressure to free stream static pressure ratio.).