The problem of two‐dimensional steady‐state laminar flow in channels with porous walls has been extended to the case of moderate to high suction or injection velocity at the walls. An exact solution of the Navier‐Stokes equations, reduced to a third‐order nonlinear differential equation with appropriate boundary conditions, is obtained. The velocity components, the pressure, and the coefficient of wall friction are expressed as functions of velocity through the porous walls, the average axial velocity of Poiseuille's flow, the coordinates and dimensions of the channel, and the physical properties of the fluid.