The entropy generation analysis of electromagnetohydrodynamic (EMHD) flow of Newtonian fluids through a curved rectangular microchannel is performed in this study. Under the assumption of thermally fully developed and the condition of constant wall heat flux, the distributions of velocity and temperature are derived analytically and numerically, which are utilized to compute the entropy generation rate. Analytical solutions of the velocity are contrasted with the numerical and experimental solutions and the agreements are excellent. The results show that the flow and the temperature depend on the strength of the electric field (S), magnetic field (Ha), aspect ratio of the rectangular cross section (alpha), curvature ratio (delta), peclet number (Pe) and viscous dissipation (Br). Then the entropy generation rates are investigated under the appropriate nondimensional parameters. The results show that the local entropy generation has a decreasing trend from the wall towards the centerline of the microchannel. Moreover, the entropy generation rate increases with the increase of S and Br but decreases with Pe and alpha. Finally, the entropy generation rate increases with the increase of Ha when Ha is small, and reaches a constant as further increase of Ha. The present endeavor can be utilized to design the efficient thermal micro-equipment. (C) 2018 Elsevier Ltd. All rights reserved.