An analysis of the fully-developed MHD free convective flow between two vertical, electrically conducting plates has been carried out. The effects of the external circuit, heat sources and modified boundary conditions on the temperature at the non-perfect thermally conducting plates have been studied. The nonlinear integro-differential equations, governing the flow, have been solved by perturbation method. Velocity and temperature profiles have been shown on graphs and the numerical values of other quantities are entered in tables. It is observed that the flow is stable at small values ofM, the Hartmann number, whereas at large values ofM, an increase inΦ 1 (the thermal conductance ratio) or λ (line heat source) leads to an instability of the flow. However, instability of the flow may be avoided by selecting the plates of high electrical conductivity.