The capacitance between any two arbitrary lattice sites of an infinite square network consisting of identical capacitors is studied analytically and numerically for a perturbed network. The perturbation is as a result of removing the bonds and from the perfect network. The equivalent capacitance is expressed in terms of the Lattice Green's Function (LGF) of the perturbed network. Solving Dyson's equation we express the LGF and the capacitance of the perturbed network in terms of those of the infinite perfect network. The asymptotic behavior of the perturbed capacitance is also studied. Finally, some numerical results are presented for the perturbed infinite square lattice, and a comparison is carried out for those of the perturbed and perfect infinite square network. © 2007 EDP Sciences.