The mixed convection flow, from a line heat source embedded at the leading edge of an adiabatic vertical surface which is immersed in a non-Darcian porous medium, is numerically studied by employing. an implicit finite difference Keller’s box method. The non-Darcian effects of convective, inertia, and solid boundary are all considered. Both the buoyancy-assisting and buoyancy-opposing flow conditions have been investigated. The results are presented for the entire range of the mixed convection parameter Lambda(L) = Gr(L)/Re-L(2), a ratio of the buoyancy-force to the inertia-force, from the purely force convection (Lambda(L) = 0) to the purely free convection (Lambda(L) --> infinity) regimes. It is shown that the non-Darcian effects decrease the peak velocities and increase the maximum temperatures. The criteria for the pure and mixed convection for a wall plume in porous media are established.