As three-dimensional computational fluid dynamics (CFD) analysis rapidly matures, the question as to whether it can replace 2D and quasi-3D methods in the aerodynamic design of turbomachinery naturally arises, since secondary flows, tip clearance flow, and corner vortices are more directly addressable through fully-3D modeling.In this paper we compare a fully-3D viscous solution method with several quasi-3D techniques (including traditional streamline curvature) as compressor design tools. State-of-the-art solvers that apply these approaches to the problem of airfoil cascade design are evaluated. Their relative strengths are revealed in their application to the design of a mixed-flow compressor impeller and in the comparison of computational results with test data.While the majority of turbomachinery design systems are still quasi-3D in their fundamental approach for some very good reasons, new design strategies that are more three-dimensional in architecture are being developed to capitalize on the strengths of fully-3D CFD. With this may come the need for a rather dramatic shift in our thinking toward the way we design compressible flow machinery. We offer our thoughts regarding the possible questions and problems, and conclude that a design system centered on fully-3D CFD offers substantial advantages for most compressor types.