Heat and mass transfer in porous medium is one of the important topics of study due to its varied applications. The current work is undertaken to understand the heat and mass transfer behavior in a porous cavity subjected to opposing flow controlled by two opposing buoyancy i.e. thermal and concentration buoyancy. The left vertical wall of the cavity is maintained at isothermal temperature Tw and concentration Cw, whereas the right vertical wall is exposed to lower temperature Tc and concertation Cc. The top and bottom surfaces of cavity are kept adiabatic such that no heat or mass transfer can cross the boundary. The investigation is particularly focused to study the effect of negative values of buoyancy ratio indicating opposing flow. The heat and mass transfer behavior is studies for various physical parameters such as Lewis number, Rayleigh number etc.