The perturbation method is used for an alyzing metal-clad multitilayer waveguides up to near cutoff.The mode propagati on characteristics in near cutoff are discussed in detail,and the results of the first and the second order approximation are compared with those obtained by ex act solution of complex eigenvalue equation.It si demonstrated that the perturba ti on method gives results in good agreement with exact results.It is also demonstr ated that the difference between results of the first and the second order appro ximation is quite small and usually the first order approximation gives sufficie ntly accurate results.