The present paper is devoted to the analysis of MHD flow and heat transfer over permeable stretching/shrinking surfaces taking into account a second order slip model. The purpose is to extract exact analytical solutions for the flow and heat valid under various physical conditions. Particular attention is paid for the effects of magnetic field on the second order slip flow conditions. Results of the present analysis in the absence of magnetic field are in excellent agreement with those available in the literature. The velocity and temperature profiles, skin friction coefficient and Nusselt number are easily examined and discussed via the closed forms obtained. For all the considered parameters, unique solutions are detected for the flow over a stretching sheet, whereas solutions turn out to be multiple for some combinations of parameters in the case of flow over a shrinking sheet. Compared to the no-slip case, as the slip is increased, the region of multiple solutions is found to extend. (c) 2012 Elsevier Ltd. All rights reserved.