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Notes: Purpose - To study the steady mixed convection boundary-layer flow of a micropolar fluid near the region of the stagnation point on a double-infinite vertical flat plate is studied. The results of this paper are important for the researchers in the area of micropolar fluids. Design/methodology/approach - For the case considered the problem reduces to a system of ordinary differential equations, which is solved numerically using the Keller-box method. This method is very efficient for solving boundary-layer problems and it can easily be applied to other general situations than that presented in this paper. Any PhD student can learn and apply it very easily. Findings - Representative results for the velocity, microrotation and temperature profiles, as well as for the reduced skin friction coefficient and the local Nusselt number have been obtained for the case of strong concentration, Prandtl number of 0.7, some values of the material parameter K and the mixed convection parameter ?(=0). Both assisting and opposing flow cases are considered. Results for the reduced skin friction coefficient and reduced local Nusselt number as well as for the reduced velocity, temperature and microrotation profiles are given in tables and figures. The obtained results are compared with ones from the open literature and it is found that they are in excellent agreement. The important conclusion is, we have been able to show that for opposing flow solutions are possible are possible only for a limited range of values of the mixed convection parameter ?. Research limitations/implications - The results of this paper are valid only in the small region around the stagnation point on a vertical surface and they are not applicable outside this region. Practical implications - The theory of micropolar fluids and also the results of the present paper can be used to explain the characteristics in certain fluids such as exotic lubricants, colloidal suspensions or polymeric fluids, liquid crystals, and animal blood. Originality/value - The paper is very well prepared, presented and readable. We believe that the results are original and important from both theoretical and application point of views.