A review of the theoretical approach for calculating the resistance between two arbitrary lattice points in an infinite square lattice (perfect and perturbed cases) is carried out using the lattice Green's function. We show how to calculate the resistance between the origin and any other site using the lattice Green's function at the origin, Go (0, 0), and its derivatives. Experimental results are obtained for a finite square network consisting of 30 ×30 identical resistors, and a comparison with those obtained theoretically is presented.