In this article, a rigorous mathematical analysis is given for a magnetohydrodynamic flow and heat transfer of a power law fluid over a vertically stretching surface. Flow phenomenon is model in a coupled partial differential equation, which are transformed to a system of ordinary differential equation by similarity transformations. The analytic solutions of the resulting non-linear ordinary differential equations are found through HAM. The pertinent effects of thermal radiation and other significant parameters on the velocity and temperature profiles are examine in detail, local skin friction coefficient and Nusselt number are provided in tabular form.