Analysis of magnetohydrodynamic natural convection boundary layer flow of an electrically conducting incompressible fluid along a heated vertical flat plate in the presence of strong cross magnetic field has been discussed. The boundary layer equations governing the flow are transformed to a convenient dimensionless form by using stream function formulation (SFF) and the numerical solution of which is obtained by employing an efficient marching order implicit finite difference scheme over the entire range of local Hartmann parameter, xi. The behavior of xi is also studied near the leading edge of the plate by embracing series solution method. However, asymptotic solution for large values of xi is established analytically, based on the inverse coordinate expansion method. Here, consideration has been given to those fluids which served as liquid metals, by taking Pr << 1. Discussion has been carried out over the results obtained for small, large and all xi regimes, for different physical parameters in terms of shear stress. tau(w), rate of heat transfer, q(w), and rate of mass transfer, m(w), in the strong cross magnetic field. Influence of local Hartmann parameter xi and Schmidt number, Sc, on velocity, temperature and concentration distributions are also shown graphically. In addition, comprehensive interpretation of energy and species distributions is also given in terms of heatlines and masslines, respectively. (C) 2012 Elsevier Ltd. All rights reserved.