In this work, the effects of thermal radiation and viscous dissipation on hydromagnetic mixed convection flow over a non-linear stretching and shrinking sheets in nanofluids have been studied numerically. Similarity equations were solved numerically using fifth-order Runge-Kutta-Fehlberg method with shooting technique. Numerical calculations are carried out for different values of physical parameters. An analysis of the results shows that the velocity and thermal fields are influenced appreciably by the magnetic field, effective Prandtl number, local Grashof number, Eckert number, power-law stretching parameter and nanoparticles volume fraction. The results for local skin-friction and local Nusselt number are also presented and discussed. Dual solutions are presented for velocity and temperature fields for various values of magnetic field and suction/injection parameters. (C) 2013 Elsevier Ltd. All rights reserved.