Summary: Results are presented of a study to implement convergence acceleration techniques based on the multigrid concept in a three-dimensional computer code developed for solving Euler and Navier-Stokes equations. The multigrid method implemented is the full approximation storage-full multigrid algorithm, which is applicable to nonlinear equations. Multigrid convergence estimates based on a single-grid or bigrid stability analysis are performed. The latter was found to yield a better prediction of practical multigrid convergence rates. In typical applications, for both laminar and turbulent flows, savings of up to 50\% in CPU time were obtained with the multigrid implementation.