A numerical investigation is accomplished for an unsteady laminar free convective flow of a viscous incompressible fluid over an impulsively started semi-infinite vertical cylinder embedded in a porous medium. The level of temperature and concentration at the surface area of the cylinder are assumed to vary as functions of power law type, in the axial coordinate. The problem is governed by a system of coupled nonlinear boundary layer equations with appropriate variable surface boundary conditions and the numerical results are obtained using an implicit finite difference scheme of Crank-Nicholson type. The effects of physical parameters on velocity, temperature and concentration profiles and also on local and mean skin-friction coefficient, Nusselt number and Sher-wood number are interpreted graphically. It is observed that the variable temperature and concentration exists in the boundary of cylinder relegates the rate of heat and mass transfer. © 2003-2012 Latin American Applied Research Journal.