In this paper, the robust stability problem of structured linear systems is analyzed. In order to preserve the structure of the initial system, the structure of the admissible perturbations is characterized. Frobenius and infinity matrix norms are used to study the robust stability of the system affected by different admissible perturbations. Upper bounds for the perturbations are obtained, which guarantee that the perturbed system remains stable. Finally, some examples are shown to illustrate the results.