This paper considers the effect of mass transfer on free convective flow and heat transfer of a viscous incompressible electrically conducting fluid past a vertical porous plate through a porous medium with time dependant permeability and oscillatory suction in presence of a transverse magnetic field and heat source, The solutions for velocity field, temperature field and concentration distribution are obtained using perturbation technique. The effects of the flow parameters such as magnetic parameter M, Grashof number for heat and mass transfer G(r), G(c), porosity parameter K-p. Prandtl number P-r, Schmidt number S-c, frequency parameter omega and heat source parameter S on the velocity, temperature and concentration distribution of the flow field and the skin friction, heat flux and the rate of mass transfer are studied analytically and presented with the aid of figures and tables. It is observed that the magnetic parameter and the Schmidt number retard the velocity of the flow field while the Grashof number for heat and mass transfer, the porosity parameter and the heat source parameter have accelerating effect on the velocity of the flow field at all points. Further, the Prandtl number reduces the temperature and the Schmidt number diminishes the concentration distribution of the flow field at all points. The skin friction coefficients tau(0) and tau increase due to increase in G(r), G(c) and K-p while decrease due to increase in S-c, M, omega and P-r Further, the rate of mass transfer S-h increases due to increase in S-c while an increase in omega results a decrease in S-h. (C) 2009 Elsevier Ltd. All rights reserved.