This paper deals with the pole location of a perturbed matrix A + E. Two perturbation classes are discussed: one with structured perturbations |E| ≤ U (a given non-negative matrix) and one where only the spectral norm ||E|| is given. Sufficient conditions are derived for the eigenvalues of A + E to be located within a circle C(α, r). The case of a diagonalizable matrix A is also considered and a sufficient condition for robust stability of a class of perturbed discrete systems is derived. Numerical examples are presented for illustration.