Free convection heat and mass transfer of non-Newtonian power law fluid from a vertical surface embedded in a doubly stratified Darcy porous medium has been analyzed. The wall temperature and concentration are constant and the medium is linearly stratified in the vertical direction with respect to both temperature and concentration. A series approximation is made for stream function, temperature and concentration in terms of thermal stratification parameter. The flow, temperature and concentration fields are affected by the complex interactions among the diffusion ratio Le, buoyancy ratio N and stratification ratio Sr. The effects of power law index parameter and double stratification of the medium on non-dimensional heat and mass transfer coefficients is discussed. © 2009 Begell House, Inc.