The paper deals with an extensive study concerning the application of an integrated multilevel methodology for the evaluation of the seismic vulnerability of the Royal Palace of Naples. In particular the paper focuses on the north-west wing of the Royal Palace of Naples. The first phase of the vulnerability evaluation, which consists in the application of the GNDT Level II method for the vulnerability index estimate and in the use of the vulnerability function for the damage index calculation, is presented. The applied methodology is suitable for a global vulnerability estimation of those structural typologies, such as historical monumental masonry building, characterized by complex structural configurations and proportions. Complementary in depth mechanical both localized and global investigations will be performed in succeeding phases. © 2008 Taylor & Francis Group, London.