We discuss the effects of the s-channel unitarization on the x and Q2 dependence of structure functions. The unitarization is implemented at the level of photoabsorption cross sections by resorting to the light-cone wave functions of virtual photons and to the diagonalization property of the scattering matrix in a basis of Fock states of the photon with fixed transverse size. The triple pomeron contribution is explicitly calculated. We find large unitarity corrections to the structure functions at x<10 -2. The results are in very good agreement with the existing NMC and the preliminary HERA data.