SummaryObtaining accurate computational results for low‐Mach‐number unsteady flows presents significant challenges for numerical schemes. In this work, we present a novel preconditioning scheme designed to provide good conditioning for these flows at all Strouhal numbers. The approach is based on the convective‐upwind split‐pressure scheme, which naturally facilitates the proper scaling of velocity and pressure dissipation terms for low‐Mach‐number unsteady flows. Unlike traditional matrix dissipation schemes, the preconditioned convective‐upwind split‐pressure scheme formulation provides scalar‐like efficiency and simplicity. Several test cases are presented for steady, unsteady, convection‐dominated, and acoustic‐dominated flows that demonstrate significant improvements in accuracy and convergence rate over traditional preconditioning schemes for a wide range of flow conditions. Copyright © 2015 John Wiley & Sons, Ltd.