The Green function approach of the electromagnetic field quantization is used to quantize the electromagnetic field near a dispersive and dissipative dielectric slabs. The dielectric function of the slab is an arbitrary complex function of frequency satisfying Kramers–Kronig relations. For the atoms with the electric dipole moment perpendicular and parallel to the slab,the vector potential operator commutation relations are used to drive the spontaneous emission rate of an atom via Fermi’s golden rule. By choosing a Lorentz model for the dielectric function of the slab, the typical spatial variations of the spontaneous emission rates near the slab are shown.