A three-dimensional multi-block Newton-Krylov flow solver for the Euler equations has been developed for steady aerodynamic flows. The solution is computed through a Jacobian-free inexact-Newton method with an approximate-Newton method for startup. The linear system at each outer iteration is solved using a Generalized Minimal Residual (GMRES) Krylov subspace algorithm. An incomplete lower/upper (ILU) factored preconditioner with reverse Cuthill-McKee reordering is utilized to increase the efficiency of GMRES. The parameters in the solver are optimized to provide a balance between speed and robustness. Tests are performed using a variety of flow conditions and grid sizes. The solver demonstrates fast convergence and good correlation with experimental data. I.