A computational procedure is described to study the mixing flow in a multilobe turbofan mixer. The predictions have been obtained using a finite volume method to solve the density-weighted time-averaged Navier-Stokes equations. Turbulence is characterized by the k-ε eddy viscosity model. To fit the irregular boundaries of the flow field, the curvilinear nonorthogonal coordinates are employed. The robustness of the computational procedure is enhanced by making use of nonstaggered grids. Results show that the streamwise vortex generated at the exit of the lobes dominates the performance of the mixing process. Comparison with experimental data indicates that good predictions can be obtained provided that sufficient inlet conditions are given.