||The present paper aims at studying the effect of microcracks opening on the diffusion and advection processes in a saturated porous medium. It is based on a micromechanical homogenization approach. The effects of porosity and microcracks are addressed in microscopic and mesoscopic levels to yield estimates of the effective diffusion and permeability tensors. Closed-form expressions and numerical results are obtained. For instance, the effect of the crack density parameter ? on the overall properties is discussed: (1) for a given value of ?, the maximum overall diffusion coefficient decreases for increasing values of crack radius; and (2) for large crack opening, the overall permeability is mainly controlled by ? and almost independent of the applied stress and the crack radius.