The effects of variable viscosity and thermal conductivity on the MHD (Magnetohydrodynamics) fluid flow, heat and mass transfer past a stretching porous surface embedded in a porous medium are investigated numerically taking both viscous and Joules dissipation in to account. The micro-inertia density is considered as variable. Viscosity and thermal conductivity are assumed to be inverse linear function of temperature. Using similarity transformations partial differential equations are converted to ordinary one and the system is then solved using Runge-Kutta method. The effects of various parameters in the problem are shown graphically and skin-friction coefficient and rate of heat transfer are shown in tabular form.