Abstract: Present study is concerned the effects of chemical reaction on free convective flow of viscous, incompressible fluid of small electrical conductivity through a porous medium bounded by an oscillating infinite porous plate in slip flow regime in presence of uniform magnetic field taking into account, the homogeneous chemical reaction of 1st order. The expressions for velocity, temperature, concentration, skin friction and rate of heat transfer are obtained. The effects of various different parameters are discussed graphically.