The steady two-dimensional laminar mixed convective boundary layer flow of a viscous incompressible electrically conducting Newtonian fluid along a moving stretching sheet embedded in a porous medium was studied numerically. We used temperature dependent viscosity and thermal conductivity and concentration dependent mass diffusvity. Further, the velocity and thermal slip boundary conditions were applied at the surface of the sheet. The governing transport equations were reduced to similarity equations using scaling group of transformation, before being sloved numerically by using the fourthfifth order Runge-Kutta-Fehlberg method from Maple 13. Our analysis revealed that the mass diffusivity parameter causes both temperature and concentration to increase whilst thermal conductivity parameter increases the temperature. It was also revealed that the rate of heat and mass transfer increased with the increasing of velocity slip, viscosity and power law parameters. Comparisons with previous published works are reported and good agreements were found.