An analysis is performed to study the shear stress, the couple-stress and heat transfer characteristics of a laminar mixed convection boundary layer flow of a micropolar fluid past an isothermal permeable plate. The governing nonsimilar boundary layer equations are analyzed using the (i) series solution for small , (ii) asymptotic solution for large and (iii) primitive-variable formulation and the stream function formulation are being used for all . The effects of the material parameters, such as, the vortex viscosity parameter, K, and the transpiration parameter,s, on the shear stress, the couple-stress and heat transfer have been investigated. The agreement between the solutions obtained from the stream-function formulation and the primitive-variable formulation is found to be excellent.