In this study, a numerical investigation is performed to analyse the flow and heat transfer characteristic of magnetohydrodynamic Casson fluid flow past a semi-infinite stretching surface in the presence of Cattaneo – Christov heat flux and nonlinear thermal radiation. Appropriate transformations are employed to reduce the governing partial differential equations into ordinary differential equations. Further, solutions of the ordinary differential equation are obtained with the aid of Runge- Kutta based shooting technique. The effect of various non- dimensional governing parameters on velocity and temperature fields for suction and injection cases are discussed with the help of graphs. Also computed and discussed the skin friction coefficient and local Nusselt number. It is found that momentum and thermal boundary layers are non-uniform for suction and injection cases. It is also found that heat transfer performance of Casson fluid is high in injection case when compared with the suction case. © 2017, Frontiers in Heat and Mass Transfer (FHMT). All rights reserved.