The paper considers the effect of velocity slip in rough porous journal bearings operating in the hydrodynamic regime. On the basis of stochastic theory of hydrodynamic lubrication of rough surfaces developed by Christensen and incorporating Beavers and Joseph slip condition at the porous bearing interface, different forms of Reynolds—type equations, as applicable to porous bearings are derived for various types of surface roughness pattern. As an application of the theory, the case of an infinitely long porous journal bearing operating under steady conditions is analyzed. It is shown that roughness—slip interaction considerably affects the bearing performance.